Primary cutaneous apocrine carcinoma: 2 cases and review of the pertinent histologic findings

Poorly differentiated cutaneous apocrine carcinomas: histopathological clues and immunohistochemical analysis for the diagnosis of this unusual neoplasm

Primary cutaneous apocrine carcinoma (PCAC) is a rare cutaneous malignancy that is derived from apocrine glands. Histologically, these tumours can appear well-differentiated where diagnosis should be relatively straightforward. However, occasionally these tumours can exhibit high-grade features, and in such instances the diagnosis can be challenging. A retrospective analysis of 12 cases of poorly differentiated PCAC, obtained from large academic institutions, was performed, and summarised below. Immunohistochemical studies were performed in all cases with antibodies against CK7, p63, CAM 5.2, GCDFP-15, GATA3, CEA, PR, ER, HER2, calponin, SMA, androgen receptor and EMA. All 12 cases were poorly differentiated; however, there were some histopathological clues to the diagnosis of apocrine carcinoma; namely, the presence of focal glandular formation, acrosyringial involvement and the presence of single 'pagetoid' cells within epidermis. All tumours were consistently positive for CK7, GATA3 and GCDFP-15 and negative for p63. The tumours had variable expression of CAM5.2, CEA, ER, PR, HER2, androgen receptor and EMA. In three cases, there was a preservation of the myoepithelial cell layer (with calponin and SMA), which also confirmed the primary cutaneous origin. PCAC is a difficult neoplasm to diagnose, as it can appear identical to metastatic carcinomas. We describe 12 cases of poorly differentiated PCAC, highlighting their salient clinical, histopathological and immunohistochemical features, and discuss the potential diagnostic pitfalls in distinguishing this entity from other malignant neoplasms. Our results indicate that a combination of thorough histological inspection coupled with an adequate battery of immunohistochemical stains is necessary to support the diagnosis of PCAC.

Coexpress of GATA-3 and ER in Anorectal and Head and Neck Squamous Cell Carcinoma Mimicking Metastatic Breast Cancer

GATA binding protein 3 (GATA-3) is a sensitive marker for breast and urothelial carcinomas. In combination with the estrogen receptor (ER), it is often used for differential diagnosis of metastatic carcinomas of breast origin. In this study, we sought to characterize GATA-3 and ER expression in squamous cell carcinoma (SqCC) of various origins to compare with breast carcinoma. Sixty-four SqCC of anorectum (35), head and neck (15), lung (11), and breast (3) as well as urothelial carcinoma (31) were included. In anorectal and head and neck SqCC, GATA-3, and ER was observed in 23/50 (46.0%) and 18/50 (36.0%) of the cases, respectively. The expression of GATA-3 and ER were present in both male and female patients without significant sex predominance. In 2 metastatic SqCC, the GATA-3 and ER expressed similar immunoreactivity compatible with their anorectal primary. Progesterone receptor was only expressed in 2 anorectal SqCC and none of head and neck SqCC or urothelial carcinomas. None of the lung SqCC expressed GATA-3 or ER (0/11). p16 was expressed in the majority of head and neck (6/12) and anorectal SqCC (26/27). Our study demonstrated that the combination of GATA-3 and ER positivity is not entirely specific for breast carcinomas, since both stains are expressed in SqCC from anorectal and head and neck origins. Clinical workup for metastatic carcinoma of suspicious breast origin should be cognizant of other tumors with a similar immunohistochemical profile (ie, SqCC).

Primary apocrine carcinoma of an unusual site

Primary apocrine carcinoma is a rare malignancy most commonly occurring in apocrine dense areas like axilla. There are only about 200 cases reported to date. We report a case of primary apocrine carcinoma present at an unusual site, that is, the arm. A wide local excision of the mass was done and was diagnosed as apocrine carcinoma on histopathological examination and was confirmed by immunohistochemistry. Wide local excision is the treatment required.

Adenocarcinoma, Not Otherwise Specified, Arising in Accessory Lacrimal Gland: A Diagnostic Challenge

Neoplasms arising in accessory lacrimal glands are rare. We describe a 33-year-old man with adenocarcinoma arising in the left lower eyelid accessory lacrimal gland. Microscopic evaluation demonstrated an infiltrative neoplasm composed of mildly to moderately pleomorphic cells with abundant eosinophilic cytoplasm and focal intracytoplasmic vacuoles, arranged predominantly in ductules. Foci of luminal and intracytoplasmic eosinophilic secretory material and occasional mucin were noted. An in situ component was identified in the gland of Wolfring. Though perineural invasion was present, high-grade nuclear features, brisk mitotic activity, and comedonecrosis were not identified. Immunohistochemical studies were notable for immunoreactivity of the tumor cells for CK7, carcinoembryonic antigen, BRST-2, androgen receptors, and HER2/neu (2+). The neoplastic cells were negative for CK20, estrogen and progesterone receptors, S-100, p63, calponin, thyroid transcription factor-1, and prostate-specific antigen. Fluorescence in situ hybridization studies for ETV6 and MAML2 rearrangements and for HER2/neu amplification were negative. Because of the absence of unifying morphologic, immunophenotypic, and molecular genetic findings, the diagnosis of adenocarcinoma, not otherwise specified, was rendered. The patient underwent comprehensive oncologic workup, which was negative for another primary tumor and metastases. He remains disease free with a follow-up of 4 years. This case illustrates the challenges encountered in applying salivary gland tumor classification to the accessory lacrimal gland neoplasm.