Tumor of follicular infundibulum with unique features

Abstract

Tumor of the follicular infundibulum is a rare benign cutaneous adnexal neoplasm with variable clinical presentation. In most cases the diagnosis is made with the help of histopathology, due to lack of a characteristic clinical presentation. The most common form is a solitary lesion, but it can be multiple or eruptive, then called infundibulomatose. This case report illustrates a patient with multiple lesions of tumor of the follicular infundibulum with bizarre aspect and atypical location.

Histologic Mimics of Basal Cell Carcinoma

“…48,77,78 Histologically, TFI has a distinctive pattern that consists of interconnecting plates of monomorphic keratinocytes arising as an extension from the basal epidermal layer ( Figure 5). 48,[76][77][78] Small, abortive follicular structures may connect to the plate from below. Neoplastic cells are pale in comparison to the surrounding normal keratinocytes.…”

“…Neoplastic cells are pale in comparison to the surrounding normal keratinocytes. 48,[76][77][78] Nuclear palisading is common. 48,[76][77][78] Although TFI may be misinterpreted as superficial BCC, TFI lacks cytologic atypia, myxoinflammatory stroma, peripheral clefting, and significant mitotic activity (Table).…”

“…48,[76][77][78] Nuclear palisading is common. 48,[76][77][78] Although TFI may be misinterpreted as superficial BCC, TFI lacks cytologic atypia, myxoinflammatory stroma, peripheral clefting, and significant mitotic activity (Table). 48,[76][77][78][79] Unlike BCC, TFI displays colonizing CK20…”

Eruptive tumors of the follicular infundibulum in photo-exposed skin

“… 4 More recently, an atypical clinical variant involving the face and posterior calves was described in the Brazilian literature. 5 We describe a similar case.…”

“…1 , 2 Similar to their solitary counterparts, multiple TFI almost always cluster on the head and neck region. However, recently Haddad et al 5 reported a case in which TFI not only involved the head and neck but also the posterior calves. We present a case with a similar clinical appearance and distribution and suggest that multiple TFI may have a predilection for the posterior calves in a subset of patients.…”