Alexis Heller

TRPS1 Reliably Stains Benign and Malignant Lesions Arising Within Vulvar Anogenital Mammary-like Glands

TRPS1 is a novel immunohistochemical marker that is known to stain normal mammary epithelium and breast carcinomas (especially triple negative carcinomas). TRPS1 staining has also been reported in normal skin appendages, benign and malignant cutaneous neoplasms, and anogenital mammary-like glands (AGMLG). However, research regarding TRPS1 staining in various neoplasms derived from AGMLG is limited. Past studies have focused on two neoplasms of AGMLG—hidradenoma papilliferum (HP) and extramammary Paget disease (EMPD). We confirm the finding that TRPS1 is positive in the epithelium of HP and we report its expression in a variety of other benign and malignant lesions derived from vulvar AGMLG, including fibroepithelial lesion (FEL), lactating adenoma (LA), fibroepithelial polyp with AGMLG, and mammary-type adenocarcinoma (MAc). The majority of TRPS1 staining was diffuse and displayed strong (3+) intensity. We show that TRPS1 is significantly more sensitive than GCDFP-15 in lesions of AGMLG and is comparable to GATA3. TRPS1 was also more sensitive than mammaglobin, but the finding did not reach statistical significance. TRPS1 demonstrated diffuse staining in these lesions significantly more often than either GCDFP-15 or mammaglobin. This study was limited by its small sample size, due to the rarity of some entities such as the malignant MAc (n=3).

Vulvar Lactating Adenoma: A Rare Representation of Mammary-Like Anogenital Glands

Mammary-like anogenital glands are considered a normal constituent of the anogenital area. These glands can have epithelial components with eccrine or apocrine features. They often undergo transformation into mammary-like lesions, including lactational changes that occur during pregnancy and the breastfeeding period. When they form mass lesions they are referred to as lactating adenomas. Their appearance can clinically be mistaken for other more common benign and malignant entities in the vulva. We describe a vulvar lesion in a 26-year-old woman. The lesion was excised and determined by histologic examination to be a benign lactating adenoma. Subsequent immunohistochemistry was performed. The epithelial cells were positive for GATA3 and estrogen receptor while negative for PAX8, supporting mammary-like differentiation. The myoepithelial markers p63 and calponin were positive at the periphery of the ducts, supporting the benign nature of this lesion.