A research report submitted to the Faculty of Health Sciences, University of Witwatersrand, in fulfillment of the requirements for the degree of Master of Medicine in the branch of Internal Medicine Johannesburg, 2015 / Lymphadenopathy is a common clinical presentation of disease in South Africa (SA), particularly in the era of Human Immunodeficiency Virus (HIV) and tuberculosis (TB) coinfection. Methods Data from 560 lymph node biopsy reports of specimens from patients older than 12 years at Chris Hani Baragwanath Academic Hospital (CHBAH) between 1 January 2010 and 31 December 2012 was extracted from the National Health Laboratory Service (NHLS), division of Anatomical Pathology. Cytology reports of lymph node fine needle aspirates (FNAs) performed prior to lymph node biopsy in 203 patients were also extracted from the NHLS. Consent was not obtained from participants for their records to be used as patient information was anonymized and de-identified prior to analysis. Results The majority of patients were female (55%) and of the African/black racial group (90%). The median age of patients was 40 years (range12-94). The most common indication for biopsy was an uncertain diagnosis (more than two differential diagnoses entertained), followed by a suspicion for lymphoma, carcinoma and TB. Overall, malignancy constituted the largest biopsy pathology group (39%), with 36% of this group being carcinoma and 27% non-Hodgkin lymphoma. 22% of the total sampled nodes displayed necrotizing granulomatous inflammation (including histopathology and cytology demonstrating definite, and suspicious for mycobacterial infection), 8% comprised HIV reactive nodes; in the remainder no specific pathology was identified (nonspecific reactive lymphoid hyperplasia). Kaposi sarcoma (KS) accounted for 3% of lymph node pathology in this sample. Concomitant lymph node pathology was diagnosed in four cases of nodal KS (29% of the subset). The co-existing pathologies were TB and Castleman disease. HIV-positive patients constituted 49% of this study sample and the majority (64%) of this subset had CD4 counts less than 350 cells/ul. 27% were HIVnegative and in the remaining nodes, the HIV status of patients was unknown. The most common lymph node pathologies in HIV-positive patients were Mycobacterial infection (31%), HIV reactive nodes (15%), non-Hodgkin lymphoma (15%) and nonspecific reactive lymphoid hyperplasia (15%). Only 9% were of Hodgkin lymphoma. In contrast, the most common lymph node pathologies in HIV-negative patients were nonspecific reactive lymphoid hyperplasia (45%), carcinoma (25%) and Mycobacterial infection (11%). In this group, non-Hodgkin lymphoma and Hodgkin lymphoma constituted 9% and 8%, respectively. There were more cases of high-grade non-Hodgkin lymphoma in the HIV-positive group compared to the HIV-negative group. FNA and lymph node biopsy had excellent agreement with regard to Hodgkin lymphoma (K 0.774, SE 0.07, 95% CI 0.606-0.882, p=0.001), and good agreement with regard to non-Hodgkin lymphoma (K 0.640, SE 0.07, 95% CI 0.472-0.807, p=0.001), carcinoma (K 0.723, SE 0.069, 95% CI 0.528-0.918, p=0.001), and mycobacterial infection (K 0.726, SE 0.07, 95% CI 0.618-0.833, p=0.001). Conclusions The most common lymph node pathologies in CHBAH are malignancies, nonspecific reactive lymphoid hyperplasia, necrotizing granulomatous inflammation and HIV reactive nodes. The distribution of disease differed in HIV-positive patients. Overall, adequate FNA samples of lymph nodes have been found to have good correlation with lymph node biopsy findings in our setting.

Indiana University-Purdue University Indianapolis (IUPUI) / Endometrial cancer is the most common gynecologic cancer in the United States, and patients with early-stage endometrioid adenocarcinoma have a favorable prognosis. Over the past decade, the gynecologic oncology community has debated whether potential harms of systematic lymph node dissection (LND) outweigh potential benefits for these patients. To minimize number of nodes removed, sentinel lymph node dissection (SLND) is under investigation as an alternative. However, ongoing uncertainty of LND/SLND best practices may result in variations in disease management and discrepant outcomes. Methods Three retrospective cohort studies examined LND/SLND use in patients with endometrioid adenocarcinoma. Two examined temporal and geographic variations, respectively, utilizing the Surveillance, Epidemiology, and End Results (SEER) 18 dataset for the years 2004 through 2015. The third used the SEER-Medicare dataset from 2003 through 2016 to quantify and compare the risk of developing 6-month post-surgical lymphedema, lymphocele, hemorrhage, ileus, infection, thrombosis, and all-cause death by number of lymph nodes removed (0, 1-4, 5-9, or 10+). Results Time trend analyses found LND increased from 2004 through 2008, followed by a significant decline through 2015. SLND was rare and did not increase significantly. Significant geographic variation existed for LND use but not SLND. Per 1,000 patients, analyses of 6-month post-surgical complications found 6.5 experienced lymphedema, 3.9 experienced lymphocele, 15.7 experienced hemorrhage, 28.7 experienced ileus, 37.1 experienced infection, 18.6 experienced thrombosis, and 19.8 died. Controlling for size of primary tumor, tumor grade, comorbidities, race/ethnicity, age at diagnosis, adjuvant chemotherapy, and radiotherapy, adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) showed greater risk for ileus (HR: 1.53; 95% CI: 1.24-1.90), infection (HR: 1.52; 95% CI: 1.25-1.83), and thrombosis (HR: 1.41; 95% CI: 1.09-1.82) when comparing removal of 10+ nodes versus 0 nodes. Conclusion Overall, these studies found significant temporal and geographic variation in LND, as well as increasing risk of post-surgical complications associated with increasing numbers of lymph nodes removed. Should continued research into SLND find strong evidence that it effectively detects cancer spread, patients may benefit through decreased risk of post-surgical ileus, infection, and thrombosis.

Objetivos: Avaliar a eficácia da injeção intraoperatória para identificação do linfonodo sentinela (LS) em câncer de mama com o uso do Dextran 500-99m-Tecnécio (Tc) e azul patente. Analisar se as doses do radiofármaco, o IMC (índice de massa corporal) e o volume da mama influenciam no tempo para migração ao LS. Metodologia: Estudo prospectivo, realizado entre abril de 2008 e junho de 2009, que incluiu 74 biópsias de LS em pacientes com câncer de mama em estádios T1N0 e T2N0. Injetou-se, após indução anestésica, de 0,5 a 1,5 mCi de Dextran 500-99m-Tc filtrado 0,22 μm na região subareolar num volume de 5 ml e 2 ml de azul patente. Resultados: Identificou-se o LS em 100% dos casos. Um LS (1,35%) estava marcado apenas com o azul patente. A taxa de identificação com o “probe” foi de 98% (73/74 casos). A dose média de radiofármaco aplicada foi 0,97 mCi + 0,22. O tempo médio para marcação do LS foi de 10,7 minutos (+ 5,7min). Identificamos em média 1,66 LS com o radioisótopo. A dose aplicada não apresentou relação com o tempo para captação (p=0,73). Quanto maior o volume da mama e IMC, maior o tempo para captação na região axilar (Pearson Correlation r=0,393 p<0,01; r=0,469 p<0,01 - respectivamente). Conclusão: A injeção intraoperatória do radiofármaco é eficaz para identificação do LS em câncer de mama. O tempo para marcação do LS é maior em pacientes com IMC elevado e mamas volumosas. Doses maiores de radiofármaco não diminuem o tempo de migração. / Objectives: To determine the identification of sentinel lymph node (SLN) in breast cancer after intraoperative injection of Dextran 500‐99mTechnetium (Tc) and blue dye. To analyze if the doses of the radioisotope, body mass index (BMI) and breast volume influence the migration time of the SLN. Methodology: Prospective study between april 2008 and june 2009, which included 74 biopsies of SLN in patients with breast cancer in stages T1N0 and T2N0. Intraoperative injection after induction of general anesthesia, 0.5 to 1.5 mCi of dextran 500‐99m‐Tc filtered 0.22 μm in the subareolar region in a volume of 5 ml and 2 ml of blue dye. Results: We identified the SLN in 100% of cases. In one case (1.35%) the SLN was marked only with the blue dye. The SLN identification rate with the probe was 98% (73/74 cases). The mean dose of radioisotope injected was 0.97 + 0.22 mCi. The average time to mark the SLN was 10.7 minutes (+ 5.7 min). We identified an average 1.66 SLN with the radioisotope. The dose had no effect on the time to capture (p = 0.73). The larger breast volume and BMI, the greater the capture time in the axillary region (Pearson Correlation r=0.393 p <0.01, r=0.469 p <0.01 - respectively). Conclusion: Intraoperative injection of the radioisotope is effective for the identification the SLN in breast cancer. Time to mark the SLN is higher in patients with high BMI and large breasts. Higher doses of radioisotope do not decrease the migration time.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Objetivos. Desenvolver um modelo experimental para identificaÃÃo de linfonodo sentinela (LS) da mama da cadela com uso de corante azul de metileno e comparÃ-lo com o azul patente, controlados por tecnÃcio. MÃtodos. O trabalho foi realizado em 23 cadelas, tendo-se observado a marcaÃÃo dos LS do primeiro par superior de mamas ao se injetarem 0,2 ml de TecnÃcio 99m ligado ao fitato (Tc 99m) e 0,5 ml de azul patente Guerbet V 2,5 % nos espaÃos subpapilares das mamas direitas e 0,2 ml de Tc-99m e 0,5 ml do azul de metileno 1 % nos mesmos espaÃos das mamas esquerdas. Resultados. Na mama direita, as tÃcnicas de biopsia de LS quando utilizados o Tc-99m e azul patente foram concordantes. Dos 23 LS estudados, somente um nÃo corou nem foi captante. O azul patente foi eficaz em 100 % quando comparado com os dois mÃtodos associados. Na mama esquerda, dos 23 LS estudados, somente dois nÃo coraram e um nÃo foi captante, sendo esta diferenÃa estatisticamente nÃo significante. A tÃcnica de biopsia do LS utilizando-se o azul de metileno apresentou-se com eficÃcia de 91,3 % quando utilizado isoladamente e de 100 % quando associado ao Tc-99m. ConclusÃo. O uso do azul de metileno associado ao radiofÃrmaco pode ser considerado como tÃcnica potencial na pesquisa transoperatÃria do LS das mamas, sendo uma opÃÃo menos onerosa e com menores efeitos alergÃnicos do que o azul patente / Objetivos. Desenvolver um modelo experimental para identificaÃÃo de linfonodo sentinela (LS) da mama da cadela com uso de corante azul de metileno e comparÃ-lo com o azul patente, controlados por tecnÃcio. MÃtodos. O trabalho foi realizado em 23 cadelas, tendo-se observado a marcaÃÃo dos LS do primeiro par superior de mamas ao se injetarem 0,2 ml de TecnÃcio 99m ligado ao fitato (Tc 99m) e 0,5 ml de azul patente Guerbet V 2,5 % nos espaÃos subpapilares das mamas direitas e 0,2 ml de Tc-99m e 0,5 ml do azul de metileno 1 % nos mesmos espaÃos das mamas esquerdas. Resultados. Na mama direita, as tÃcnicas de biopsia de LS quando utilizados o Tc-99m e azul patente foram concordantes. Dos 23 LS estudados, somente um nÃo corou nem foi captante. O azul patente foi eficaz em 100 % quando comparado com os dois mÃtodos associados. Na mama esquerda, dos 23 LS estudados, somente dois nÃo coraram e um nÃo foi captante, sendo esta diferenÃa estatisticamente nÃo significante. A tÃcnica de biopsia do LS utilizando-se o azul de metileno apresentou-se com eficÃcia de 91,3 % quando utilizado isoladamente e de 100 % quando associado ao Tc-99m. ConclusÃo. O uso do azul de metileno associado ao radiofÃrmaco pode ser considerado como tÃcnica potencial na pesquisa transoperatÃria do LS das mamas, sendo uma opÃÃo menos onerosa e com menores efeitos alergÃnicos do que o azul patente / Objectives. To develop an experimental model for identification of sentinel lymph node (SLN) of breast bitch with the use of methylene blue and compares it with the patent blue, both associated with technetium. Methods. 23 dogs, there was the marking of the SLN of the first upper pair of breasts to inject 0.2 ml of Tc-99m phytate bound to (99m) and 0.5 ml of patent blue Guerbet V 2,5 % in subpapilar spaces right breast and 0.2 ml of 99mTc and 0.5 ml of 1% methylene blue in the same spaces left breast. Results. In the right breast biopsy techniques using 99mTc SLN and blue dye are in agreement. Of the 23 SLN studied, only one was not flushed nor uptake. The patent blue was effective in 100% when compared with the two methods together. The left breast of 23 SLN studied, only two non-stained and one was not uptake, this difference was not statistically significant. The SLN biopsy technique using methylene blue appeared with a 91.3% effectiveness when used alone and 100% when associated with 99mTc. Conclusion: The use of methylene blue associated with the radiotracer technique can be considered as potential research intraoperative SLN of breast, suggesting a less costly and less allergenic effects that blue patent. / Objectives. To develop an experimental model for identification of sentinel lymph node (SLN) of breast bitch with the use of methylene blue and compares it with the patent blue, both associated with technetium. Methods. 23 dogs, there was the marking of the SLN of the first upper pair of breasts to inject 0.2 ml of Tc-99m phytate bound to (99m) and 0.5 ml of patent blue Guerbet V 2,5 % in subpapilar spaces right breast and 0.2 ml of 99mTc and 0.5 ml of 1% methylene blue in the same spaces left breast. Results. In the right breast biopsy techniques using 99mTc SLN and blue dye are in agreement. Of the 23 SLN studied, only one was not flushed nor uptake. The patent blue was effective in 100% when compared with the two methods together. The left breast of 23 SLN studied, only two non-stained and one was not uptake, this difference was not statistically significant. The SLN biopsy technique using methylene blue appeared with a 91.3% effectiveness when used alone and 100% when associated with 99mTc. Conclusion: The use of methylene blue associated with the radiotracer technique can be considered as potential research intraoperative SLN of breast, suggesting a less costly and less allergenic effects that blue patent.

Accurate detection of the spread of cancer is critical for planning the best treatment strategy for a patient. Currently, an invasive sentinel lymph node biopsy is commonly used to detect metastases after a primary tumor is detected. This procedure results in patient morbidity, requires weeks of waiting, and is prone to sampling error. This dissertation presents new developments in an emerging biomedical imaging modality – photoacoustic imaging – and their application to improving the detection of metastases in the lymphatic system in a metastatic mouse model of squamous cell carcinoma of the oral cavity. Label-free spectroscopic photoacoustic imaging is demonstrated to detect hypoxia that results from the development of sub-millimeter cancer foci in the lymph node. In order to improve the sensitivity to micrometastases, molecularly-activated plasmonic nanosensers which are targeted to the epidermal growth factor receptor are introduced. The nanosensors are demonstrated to detect metastases consisting of only a few tens of cells. Improvements to spectroscopic photoacoustic imaging are then demonstrated by selecting imaging wavelengths based on the spectral properties of the optical absorbers. Finally, a new contrast agent – silica-coated gold nanoplates – are used to map the sentinel lymph node with high contrast. The final result is a set of tools that can be used to noninvasively detect micrometastases and improve molecular photoacoustic imaging. / text

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2007. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 4 uppsatser.

Objetivos: Avaliar a eficácia da injeção intraoperatória para identificação do linfonodo sentinela (LS) em câncer de mama com o uso do Dextran 500-99m-Tecnécio (Tc) e azul patente. Analisar se as doses do radiofármaco, o IMC (índice de massa corporal) e o volume da mama influenciam no tempo para migração ao LS. Metodologia: Estudo prospectivo, realizado entre abril de 2008 e junho de 2009, que incluiu 74 biópsias de LS em pacientes com câncer de mama em estádios T1N0 e T2N0. Injetou-se, após indução anestésica, de 0,5 a 1,5 mCi de Dextran 500-99m-Tc filtrado 0,22 μm na região subareolar num volume de 5 ml e 2 ml de azul patente. Resultados: Identificou-se o LS em 100% dos casos. Um LS (1,35%) estava marcado apenas com o azul patente. A taxa de identificação com o “probe” foi de 98% (73/74 casos). A dose média de radiofármaco aplicada foi 0,97 mCi + 0,22. O tempo médio para marcação do LS foi de 10,7 minutos (+ 5,7min). Identificamos em média 1,66 LS com o radioisótopo. A dose aplicada não apresentou relação com o tempo para captação (p=0,73). Quanto maior o volume da mama e IMC, maior o tempo para captação na região axilar (Pearson Correlation r=0,393 p<0,01; r=0,469 p<0,01 - respectivamente). Conclusão: A injeção intraoperatória do radiofármaco é eficaz para identificação do LS em câncer de mama. O tempo para marcação do LS é maior em pacientes com IMC elevado e mamas volumosas. Doses maiores de radiofármaco não diminuem o tempo de migração. / Objectives: To determine the identification of sentinel lymph node (SLN) in breast cancer after intraoperative injection of Dextran 500‐99mTechnetium (Tc) and blue dye. To analyze if the doses of the radioisotope, body mass index (BMI) and breast volume influence the migration time of the SLN. Methodology: Prospective study between april 2008 and june 2009, which included 74 biopsies of SLN in patients with breast cancer in stages T1N0 and T2N0. Intraoperative injection after induction of general anesthesia, 0.5 to 1.5 mCi of dextran 500‐99m‐Tc filtered 0.22 μm in the subareolar region in a volume of 5 ml and 2 ml of blue dye. Results: We identified the SLN in 100% of cases. In one case (1.35%) the SLN was marked only with the blue dye. The SLN identification rate with the probe was 98% (73/74 cases). The mean dose of radioisotope injected was 0.97 + 0.22 mCi. The average time to mark the SLN was 10.7 minutes (+ 5.7 min). We identified an average 1.66 SLN with the radioisotope. The dose had no effect on the time to capture (p = 0.73). The larger breast volume and BMI, the greater the capture time in the axillary region (Pearson Correlation r=0.393 p <0.01, r=0.469 p <0.01 - respectively). Conclusion: Intraoperative injection of the radioisotope is effective for the identification the SLN in breast cancer. Time to mark the SLN is higher in patients with high BMI and large breasts. Higher doses of radioisotope do not decrease the migration time.

Objetivos: Avaliar a eficácia da injeção intraoperatória para identificação do linfonodo sentinela (LS) em câncer de mama com o uso do Dextran 500-99m-Tecnécio (Tc) e azul patente. Analisar se as doses do radiofármaco, o IMC (índice de massa corporal) e o volume da mama influenciam no tempo para migração ao LS. Metodologia: Estudo prospectivo, realizado entre abril de 2008 e junho de 2009, que incluiu 74 biópsias de LS em pacientes com câncer de mama em estádios T1N0 e T2N0. Injetou-se, após indução anestésica, de 0,5 a 1,5 mCi de Dextran 500-99m-Tc filtrado 0,22 μm na região subareolar num volume de 5 ml e 2 ml de azul patente. Resultados: Identificou-se o LS em 100% dos casos. Um LS (1,35%) estava marcado apenas com o azul patente. A taxa de identificação com o “probe” foi de 98% (73/74 casos). A dose média de radiofármaco aplicada foi 0,97 mCi + 0,22. O tempo médio para marcação do LS foi de 10,7 minutos (+ 5,7min). Identificamos em média 1,66 LS com o radioisótopo. A dose aplicada não apresentou relação com o tempo para captação (p=0,73). Quanto maior o volume da mama e IMC, maior o tempo para captação na região axilar (Pearson Correlation r=0,393 p<0,01; r=0,469 p<0,01 - respectivamente). Conclusão: A injeção intraoperatória do radiofármaco é eficaz para identificação do LS em câncer de mama. O tempo para marcação do LS é maior em pacientes com IMC elevado e mamas volumosas. Doses maiores de radiofármaco não diminuem o tempo de migração. / Objectives: To determine the identification of sentinel lymph node (SLN) in breast cancer after intraoperative injection of Dextran 500‐99mTechnetium (Tc) and blue dye. To analyze if the doses of the radioisotope, body mass index (BMI) and breast volume influence the migration time of the SLN. Methodology: Prospective study between april 2008 and june 2009, which included 74 biopsies of SLN in patients with breast cancer in stages T1N0 and T2N0. Intraoperative injection after induction of general anesthesia, 0.5 to 1.5 mCi of dextran 500‐99m‐Tc filtered 0.22 μm in the subareolar region in a volume of 5 ml and 2 ml of blue dye. Results: We identified the SLN in 100% of cases. In one case (1.35%) the SLN was marked only with the blue dye. The SLN identification rate with the probe was 98% (73/74 cases). The mean dose of radioisotope injected was 0.97 + 0.22 mCi. The average time to mark the SLN was 10.7 minutes (+ 5.7 min). We identified an average 1.66 SLN with the radioisotope. The dose had no effect on the time to capture (p = 0.73). The larger breast volume and BMI, the greater the capture time in the axillary region (Pearson Correlation r=0.393 p <0.01, r=0.469 p <0.01 - respectively). Conclusion: Intraoperative injection of the radioisotope is effective for the identification the SLN in breast cancer. Time to mark the SLN is higher in patients with high BMI and large breasts. Higher doses of radioisotope do not decrease the migration time.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Este trabalho aborda a influÃncia da incisÃo para-areolar no quadrante superior externo da mama, na localizaÃÃo do linfonodo sentinela em modelo canino. A BiÃpsia do linfonodo sentinela (BLS) à um mÃtodo de amostragem seletiva, minimamente invasivo, altamente sensÃvel em predizer o estado axilar, podendo evitar o esvaziamento ganglionar em pacientes sem comprometimento metastÃtico. Mulheres, com cirurgias mamÃrias previas, foram excluÃdas da realizaÃÃo da BLS por muitos cirurgiÃes por acreditar que teriam um Ãndice de falso negativo elevado, inviabilizando o mÃtodo. Outros mastologistas passaram a empregar, empiricamente, a injeÃÃo do marcador corante ou radioativo acima da borda da incisÃo prÃvia, porÃm fica a dÃvida se o gÃnglio identificado à realmente o Linfonodo Sentinela (LS). Este trabalho experimental, em modelo canino, tem como objetivo identificar a influÃncia das incisÃes para-areolares prÃvias, no quadrante superior externo (QSE) da mama na identificaÃÃo do linfonodo sentinela. à utilizado o radiocolÃide TecnÃcio99 injetado na derme sub-areolar das mamas torÃcicas craniais, para marcar o LS. Esperado o tempo de migraÃÃo do radiofÃrmaco para axila e identificado o local de marcaÃÃo com probe. Procede-se incisÃo arciforme para- areolar no QSE, entre 9 e 12h à direita e 12 e 3 h à esquerda, a 2cm do mamilo. O corante azul patente Ã, entÃo, injetado na borda superior destas incisÃes. No ponto marcado com o gama-probe à realizada a incisÃo axilar mÃnima, onde o LS à identificado com auxÃlio do probe, que capta a radiaÃÃo do gÃnglio, eou pela visualizaÃÃo direta do linfonodo impregnado com o corante. SÃo comparadas duas tÃcnicas de local de injeÃÃo e a concordÃncia entre os mÃtodos de identificaÃÃo do LS. Os experimentos da pesquisa ocorreram entre Janeiro 2008 e Maio 2009. A amostra à composta de 40 mamas torÃcicas craniais, oriundas de 23 cadelas adultas, sem raÃa definida, da espÃcie Canis familiaris. A anÃlise estatÃstica foi realizada com o auxÃlio do programa Graphpad e utilizados o Teste de McNemar e Coeficiente de ConcordÃncia de Kappa. Os resultados demonstram que em 95% das mamas estudadas (3840) obtiveram o LS identificado na axila apÃs a injeÃÃo de tecnÃcio na regiÃo subareolar e em 82% dos casos (33/40) coraram com azul patente injetado no bordo superior da incisÃo padronizada. Os resultados obtidos indicam a concordÃncia entre os mÃtodos em 82% dos casos na identificaÃÃo do LS (3340). As incisÃes para-areolares prÃvias, nos quadrantes superiores externos, das mamas torÃcicas craniais da cadela, nÃo demonstram interferir, de maneira significante, na BLS quando o corante à injetado na borda superior da incisÃo. O linfonodo encontrado a partir de injeÃÃo na borda superior da incisÃo previa, corresponde ao linfonodo sentinela da mama da cadela, em 95% dos casos (3233). / This paper discusses the influence of para-areolar incision in the upper outer quadrant of the breast for the location of the sentinel lymph node in canine model. Sentinel lymph node biopsy (SLNB)&#8213;a minimally invasive selective sampling technique highly predictive of the condition of the armpit&#8213;can spare metastasis-free patients from unnecessary axillary dissection. The high incidence of false-negative results has led many surgeons to no longer indicate SLNB to women with previous breast surgery. Some mastologists prefer to empirically inject a dye or radio-labelled marker above the border of the previous incision, though it is not always clear if the identified ganglion is in fact the sentinel lymph node. The objective of the present study was to evaluate the influence of previous para-areolar incisions in the upper outer quadrant (UOQ) of the breast upon the identification of the sentinel lymph node (SLN) in a canine model. The SLN was marked with Technetium-99m (99mTc) injected into the subareolar skin of the cranial breast. Once the marker had migrated to the axilla and the marked site had been identified with a gamma probe, an arcuate para-areolar incision was performed 2 cm from the nipple in the UOQ (between the 9 and 12 oâclock position on the right side, and between the 12 and 3 oâclock position on the left side). Patent blue dye was then injected above the upper border of the incision. At the marked site a minimal axillary incision was made and the SLN was identified by gamma probe and/or by direct visualization of the dye. The agreement between the two injection sites and the two SLN identification methods was determined. The experiments were carried out between January 2008 and May 2009 on a sample of 40 cranial breasts of 23 adult females of the species Canis familiaris. Using the statistics software Graphpad, the data were submitted to the McNemar test and the Kappa agreement coefficient was calculated. Our findings show that in 95% (38/40) of the breasts the SLN was identified by injection of 99mTc in the subareolar region, and that in 82% (33/40) of cases the SLN was identified by injection of patent blue dye above the upper border of the incision. Thus, the methods agreed in 82% (33/40) of cases. Previous para-areolar incisions in the UOQ of the cranial breasts did not interfere significantly with the biopsy when the dye was injected above the upper border of the incision. The lymph node identified by injection above the upper border of the previous incision corresponded to the SLN in 95% (32/33) of cases.