A clinical, pathological and immunohistochemical series of 9 cases of primary cutaneous apocrine carcinomas of the head and neck.

Background/Objectives: Primary cutaneous apocrine carcinoma is a rare malignant adnexal skin tumour that can recur locally, spread to regional lymph nodes and metastatize to visceral organs. Wide dissemination and death from disease are much less common. The axilla is the most common site of presentation. It is infrequently reported in the head and neck region. Methods: All cases diagnosed as primary cutaneous apocrine carcinoma of the head and neck were retrospectively collected from the archives of the Division of Pathological Anatomy, University of Florence from 1996 to 2016. There was no history or clinical evidence of breast cancer. Clinical data and follow‐up were collected by the clinicians. Results: Nine cases were found, with a mean age of 76 years, ranging in size between 0.3 and 3.5 cm. Clinically, they were frequently mistaken for basal cell carcinomas. Histopathologically, all the tumours showed decapitation secretion, a tubular, solid or mixed (tubulo‐papillary and solid‐tubular) growth pattern and were predominantly classified as grade 2 tumours. GCDFP‐15 and hormone receptors were variably expressed. HER2 and podoplanin were negative in all cases. In one case, spreading to regional lymph nodes was observed. No cases were associated with death due to the disease. Conclusion: As immunohistochemical analysis lacks specificity in distinguishing primary cutaneous apocrine carcinoma from a cutaneous metastasis of breast carcinoma, detailed clinical history, breast examination, adequate treatment and follow‐up are necessary to confirm a diagnosis of primary cutaneous apocrine carcinoma. [ABSTRACT FROM AUTHOR]