Background: Trichoblastic carcinoma (or malignant trichoblastoma) is a rare malignant cancer of adnexal structures with morphological features that in some cases are reminiscent of a trichoblastoma. Trichoblastic carcinoma is underdiagnosed as it is a rather recent entity which is still not recognized as such by all pathologists. The differential diagnosis with basal cell carcinoma is often difficult to make and the optimal treatment has not yet been established.
Case report: We report the case of a 43-year-old patient who underwent surgical excision and adjuvant radiotherapy for a growing mass of 40 × 48 mm located in the lumbar right paraspinal skin. The pathological findings demonstrated a trichoblastic carcinoma. The clinicopathological profile, the histogenesis, and the difficulties related to the histopathological diagnosis and treatment of this rare entity are discussed in this article.
Conclusion: Although the published reports on this disease are few, surgery should be considered the standard therapeutic approach for trichoblastic carcinomas. Selected cases presenting clinical features of local aggressiveness can safely be treated with adjuvant irradiation to improve local control. However, acute and particularly late toxicities need to be taken into account in the decision.