# Primary Cutaneous Cribriform Apocrine Carcinoma: A Case Report and Narrative Review

## TL;DR

This paper reports a rare skin cancer case and reviews its unique features to distinguish it from more serious cancers.

## Contribution

The paper presents a new case of PCCAC and provides a narrative review to clarify its histopathological and immunohistochemical distinctions.

## Key findings

- PCCAC is characterized by cribriform nests and tubules of atypical epithelial cells.
- Immunohistochemical staining showed CK7, CK5/6, BER-EP4, CD117, and S100 positivity.
- Distinguishing PCCAC from metastatic malignancies is critical for proper diagnosis.

## Abstract

Primary Cutaneous Cribriform Apocrine Carcinoma (PCCAC) is a rare, inert low-grade cutaneous malignancy that is diagnosed on histopathologic assessment. PCCAC usually presents in middle-aged adults as a solitary, subcutaneous nodule on the extremities. Characterized by anastomosing tubules and solid/cribriform nests of atypical epithelial cells generating a sieve-like display, the tumor is a histopathological variant of apocrine metaplasia of the skin. PCCAC also follows characteristic staining patterns. It is important to distinguish PCCAC from other similar histological variants, which may hold more grievous indications.

A 47-year-old female presented with an enlarging, itchy growth of several months on her back. On physical exam, an indurated pink, nontender papule of 8 mm on the left lateral side wall was noted. Histopathology demonstrated a well-circumscribed, pandermal tumor composed of anastomosing solid and cribriform nests, tubules, and cords of mildly atypical, eosinophilic epithelial cells forming a glandular lumina. An immunohistochemical study revealed the tumoral epithelium to express CK7, CK5/6, BER-EP4, CD117 (C-kit), and S100. Positive EMA and CEA staining highlighted intratumoral glandular ductal differentiation and apocrine secretion. Immunohistochemical stains for CK20, GATA-3, and p63 were negative.

We present this case to distinguish the histological attributes of PCCAC and help differentiate it from more concerning visceral metastatic malignancies. We follow with a narrative review of the histopathologic differential for PCCAC and feature reconciliation of corresponding staining patterns reported in the literature.