Desmoplastic Trichilemmoma Arising Within a Nevus Sebaceus

Abstract

A 74-year-old man presented with a tumor on his scalp that he had since birth. The authors observed a verrucous pink crusted plaque. The tumor was clinically diagnosed as nevus sebaceus and was removed. Histopathologic study showed, arising from nevus sebaceus, a lobular neoplasm with the classic features of trichilemmoma. Desmoplasia was present in the center of the trichilemmomatous area. This description is typical of a special, uncommon type of trichilemmoma that histologically mimics invasive carcinoma.

Mucoepidermoid (Adenosquamous) Carcinoma, Trichoblastoma, Trichilemmoma, Sebaceous Adenoma, Tumor of Follicular Infundibulum and Syringocystadenoma Papilliferum Arising Within 2 Persistent Lesions of Nevus Sebaceous: Report of a Case

“…2,3,6,7 Desmoplastic change surrounding the neoplastic cells which separated the neoplastic cells into small nests or cords of neoplastic cells was seen in some trichilemmomal nodules. These features resembled the desmoplastic trichilemmoma reported by Roson et al 12 The fifth tumor in our patient was ambiguous sebaceous adenoma. Differential diagnosis included sebaceoma and sebaceous hyperplasia.…”

“…These features resembled a desmoplastic trichilemmoma that was previously described in SNJ. 12 MEC, in our case, presented as a disorganized solid and papillary outgrowth, which consisted of mixture of dysplastic squamous cells and mucigenic cells. Invasion deep into the reticular dermis was also noted (Figs.…”

Linear trichilemmoma following a blaschkoid pattern: a clinical dilemma

“…Trichilemmoma may occur as a secondary neoplasm within naevus sebaceus. The variant desmoplastic trichilemmoma is especially common in this context . On histopathology, there is lobular proliferation consisting of glycogen containing outer root sheath.…”

Triquilemoma Desmoplástico em Nevo Sebáceo do Couro Cabeludo

“…Clinically, trichilemmomas may present either as solitary nondescript verrucous small papules at the central part of the face or, rarely, as multiple lesions at the same location, a circumstance where -together with sclerotic fibromas and acrokeratosis verruciformis -the diagnosis of Cowden`s syndrome should be evoked. Trichilemmomas may also, although rarely, occur as a secondary neoplasm within the milieu of a nevus sebaceous (NS) 3 the very similar way varied appendageal tumours do, in what is regarded by some as a third stage in the natural history of NS. 4,5 .…”

“…When cells merge on the dense stroma, the lobular pattern is disrupted and cells tend to cluster in irregular cords or nests, with occasional dyskeratosis or necrosis, thus simulating an invasive carcinoma. 2,3,6 The case of a 56 year old Caucasian male who developed a desmoplastic trichilemmoma within a nevus sebaceous of the scalp is presented.…”