Abstract:

Spiradenoma is a benign adnexal neoplasm that oftentimes is painful and typically manifests as a nodule on the head or trunk. Rarely, spiradenoma can undergo malignant transformation. Infrequently, adenoid cystic carcinoma-like features have been described in spiradenoma and, more rarely, in spiradenocarcinoma. Primary cutaneous adenoid cystic carcinoma (PCACC) is a rare low-grade, often painless, tumor that typically occurs on the scalp and in middle-aged adults. We add to this literature by reporting the case of a spiradenocarcinoma with adenoid-cystic like features. A 60-year old female presented at an outside institution for a suspected lipoma v. sebaceous cyst, measuring approximately 6.25 cm on the left, lateral anterior chest. This was received as multiple fragments without orientation. On initial read, the lesion was called “poorly differentiated carcinoma”, with a differential of a tumor of breast origin or malignant transformation of a sweat gland neoplasm. The patient was referred to our institution for definitive therapy. At that time, it was noted that there was an ipsilateral, enlarged suspected lymph node. On excision, similar histologic features were noted to the prior excisional biopsy. There was a transition from conventional spiradenoma with more solid growth, open chromatin, and some vesicular nuclei with associated squamous differentiation. In addition, mitotic figures were easily identified in this transition area. There was also the presence of adenoid cystic carcinoma-like features that were very focal and contained cribriform regions of epithelial cells arranged around glandular regions filled with mucinous like material. On further work-up, it was noted that GATA-3 was negative with positive CK7, Sox-10, CK5/6, and p63 labelling. Spiradenocarcinomas are rare adnexal carcinomas and, herein, we present an unusual variant with adenoid cystic carcinoma-like features that have recently been described in several case reports.

Financial Disclosure:
No current or relevant financial relationships exist.

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Jay Hwang, MD