Primary Cutaneous Cribriform Apocrine Carcinoma.

BACKGROUND Primary cutaneous cribriform apocrine carcinoma is a histopathological variant of apocrine adenocarcinoma (AA) of the skin, which is a rare, low-grade malignancy. While low-grade in nature, cutaneous cribriform apocrine carcinoma can mimic a metastatic manifestation of a visceral or breast malignancy, and is important to distinguish as primary through clinical history, histology, and immunohistochemical studies, if indicated. CASE REPORT A 56-year-old man with past medical history remarkable for basal cell carcinoma and hypertension presented with a 12-month history of a slowly enlarging, asymptomatic nodule on his right anterior medial lower leg. Physical examination revealed a 12×9 mm indurated and erythematous nodule with no other masses or lymphadenopathy detected. Histology demonstrated a well-circumscribed proliferation of epithelial cells in fibrosing granulation tissue-like stroma having the delicate cross-bridging of a cribriform carcinoma. Immunohistochemical studies were significant for positive high-molecular-weight keratin and cytokeratin, focal positivity for carcinoembryonic antigen (CEA) and S100, with negative results for prostate-specific antigen (PSA) and cytokeratin 20. CONCLUSIONS Clinicians should maintain a high index of suspicion for metastasis when cutaneous cribriform apocrine carcinoma is diagnosed. The use of clinical history and appropriate laboratory workup with parameters such as age and sex can guide workup. After a wider excision with clear margins, follow-up for evidence of recurrence or metastasis is recommended, as the limited number of reported cases suggests that this assumption cannot be made with certainty.