Trichoblastic carcinoma arising in trichoepithelioma in Brooke–Spiegler syndrome

Brooke–Spiegler syndrome (BSS) is a rare autosomal dominant disease characterized by the development of multiple cutaneous adnexal neoplasms namely cylindroma, trichoepithelioma and spiradenoma. The neoplasms associated with this syndrome are generally benign, but rarely they may undergo malignant transformation. A 63-year-old male presented with an ulcerated nodular lesion over glabella and multiple asymptomatic nodular lesions over face, scalp, chest and limbs. His father, grandfather and paternal cousins had history of similar lesions. Histopathological examination revealed trichoblastic carcinoma arising from trichoepithelioma over glabella and cylindroma on the chest. With these findings we arrived at a diagnosis of BSS with malignant transformation of trichoepithelioma. Trichoblastic carcinoma arising in trichoepithelioma in a patient with BSS is extremely rare with only a single case reported in literature.

A giant trichoblastic carcinoma

Trichoblastic carcinoma usually occurs as a malignant transformation of the trichoblastoma, but is very rare. A 25-year-old man was admitted with trichoblastoma in the nuchal area with frequent recurrences since birth. The preoperative neck magnetic resonance image revealed lobulated soft tissue lesions involving superficial fascia and infiltrating into both proximal trapezius muscles. In our department, wide excision and reconstruction with a free anterolateral thigh flap were performed. Histological examination revealed skin adnexal carcinoma, originating from the hair follicles, consistent with trichoblastic carcinoma. There was no palpable mass 5 years postoperatively, and there was no recurrence on follow-up positron emission tomography-computed tomography. Trichoblastic carcinomas are rare and difficult to diagnose, but histopathological findings include atypical basaloid keratinocytes with crowded, hyperchromatic nuclei, and increased mitotic activity. The presence of hypercellular stroma is a criterion for distinguishing trichoblastic carcinoma from basal cell carcinoma. A rare giant trichoblastic carcinoma was reported, which was the biggest one in the literature.

A Case of Trichobalstic Carcinoma / 대한피부과학회지

Trichoblastoma is a benign cutaneous neoplasm that consists of follicular germinative cells. There have only been a few case reports describing the malignant counterpart of trichoblastoma. We report trichoblastic neoplasms that show histological features of malignancy. The histological sections revealed locally aggressive neoplasms showing prominent differentiation towards hair germ and follicular sheath with formation of papillary mesenchymal bodies and follicular bulb-like structures. The tumor was widely excised with a clear margin. No sign of recurrence has been noted 1 year later.