# Radical resection and sentinel lymph node evaluation of mammary-like adenocarcinoma of the vulva (MLAV) with somatic BRCA1 mutation

## TL;DR

A rare vulvar cancer resembling breast cancer was treated with radical surgery and lymph node evaluation, and a BRCA1 mutation was found to guide potential therapies.

## Contribution

Demonstrates feasibility of sentinel lymph node mapping and highlights the importance of genetic testing in mammary-like vulvar adenocarcinoma.

## Key findings

- Sentinel lymph node mapping with ICG dye is feasible for staging mammary-like vulvar adenocarcinoma.
- BRCA1 somatic mutations in MLAV may inform targeted therapy options.
- Radical resection and lymph node assessment can achieve T2N0M0 staging in MLAV.

## Abstract

•MLAV arises in the vulva from mammary-like anogenital glands histologically similar to breast cancer.•Sentinel lymph node mapping and biopsies with indocyanine green (ICG) dye is feasible for staging MLAV.•Somatic and germline testing should be considered as part of the work up for MLAV.•Pathogenic somatic variants like BRCA1 can potentially direct targeted therapies.

MLAV arises in the vulva from mammary-like anogenital glands histologically similar to breast cancer.

Sentinel lymph node mapping and biopsies with indocyanine green (ICG) dye is feasible for staging MLAV.

Somatic and germline testing should be considered as part of the work up for MLAV.

Pathogenic somatic variants like BRCA1 can potentially direct targeted therapies.

Mammary-like gland adenocarcinoma of the vulva is a rare and aggressive form of vulvar cancer with histopathologic resemblance to breast cancer. This rare type of vulvar cancer develops from primary metaplasia of mammary-like anogenital glands, more recently discovered anatomic components of the anogenital region.

We present a 77-year-old African-American female with a six-month history of painless, left lower vulvar lesion referred to our cancer center following confirmatory biopsy of invasive mammary type adenocarcinoma. Preoperative PET CT demonstrating focal avidity (SUV 7.8) in the vulvar region with no evidence of metastatic disease. She underwent exam under anesthesia, left radical vulvar excision with primary closure, left inguinal sentinel lymph node mapping and biopsy for a TNM stage of T2N0M0 and vulvar FIGO stage IB grade 2. Somatic testing was significant for a BRCA1 mutation (variant p.S770, c.2309C>G).

Mammary-like gland adenocarcinoma of the vulva is a rare but aggressive neoplasm that presents diagnostic challenges due to its resemblance to breast carcinoma. Radical resection and sentinel lymph node assessment is feasible. Melanocytic skin types pose a unique set of differences regarding detection, diagnosis and potential genomic variations such as BRCA1 mutation in our patient. Genetic and genomic assessments should be considered to further guide optimal therapeutic options.