Trichoepithelioma: a 19‐year clinicopathologic re‐evaluation

Abstract

Accurate histopathologic distinction between trichoepithelioma (TE) and basal cell carcinoma (BCC) may be challenging. From 97 cases diagnosed as TE during the period 1979-1997, 73 available cases were studied with regard to: 1) stroma; 2) retraction effect; 3) papillary-mesenchymal bodies (PMB); 4) amyloid; 5) mitotic figures; 6) apoptotic cells; 7) inflammation; 8) granuloma; and 9) calcification. A judgment was made regarding diagnosis. The patients' medical records were subsequently reviewed for clinical features and possible recurrence. The diagnosis of TE was confirmed histologically in 48 (65%) of 73 cases. Fifteen cases (21%) were reclassified as BCC (RC-BCC), eight other cases (11%) were reclassified as other lesions, and two additional cases (3%) could not be confidently classified as either TE or BCC. The most helpful differentiating features were the presence of retraction effect (in 100% of RC-BCC vs. 37% of TE), myxoid stroma (in 80% of RC-BCC vs. 12% of TE) and PMB (in 20% of RC-BCC vs. 81% of TE). Unexpected findings in TE were detection of amyloid in 33%, apoptotic cells in 100%, and mitotic figures in 46%. Five of the 15 RC-BCC have recurred (33%), whereas there have been no recurrences in the confirmed TE group. A constellation of histopathologic criteria may help to discriminate problematic examples of trichoepithelioma from basal cell carcinoma.

Merkel Cell-Poor Trichoblastoma With Basal Cell Carcinoma-Like Foci

“…Although both lesions were clinically diagnosed as nodular BCC, each clinically showed a well-circumscribed, symmetrical lesion without ulceration, but neither the Although trichoblastoma is clearly a benign neoplasm of follicular germinative cells, and BCC is its malignant counterpart, the two are considered to represent different points along the same neoplastic spectrum based on the common molecular pathogenesis. [1][2][3] There are four types of lesions demonstrating the same neoplastic spectrum: (1) a lesion with almost equal histopathological components of both trichoblastoma and BCC and a clear border between the two components, 8,9,14 (2) trichoblastoma with a foci of BCC, 13 (3) BCC with a foci of trichoblastoma, 10,11,15,16 and (4) diagnostically confusing cases, whether trichoblastoma or BCC, with both features having no clear border between the two components. 12 There have been various attempts to differentiate trichoblastoma from BCC using immunohistochemical markers, including CD34-positive stromal cells or the staining pattern of bcl-2 in neoplastic aggregations.…”

Eyelid Basal Cell Carcinoma After Trichoepithelioma: A Case Report

“…5 Histopatolojik olarak konvansiyonel ve desmoplastik olmak üzere iki tipi mevcuttur. 6 Tanıda tıraş biyopsi ve insizyonel biyopsi kullanılır.…”

The cytology of giant solitary trichoepithelioma

“…[3] The papillary mesenchymal bodies are distinct fibroblastic aggregations that represent abortive attempts to form papillary mesenchyme responsible for hair induction. [3] Trichelemmal keratinization, which is abrupt and complete is represented by islands of basaloid cells surrounded by glassy eosinophilic areas.…”