Fibrofolliculoma and Trichodiscoma

David Cassarino, MD, PhD

Key Facts

Terminology

Closely related hamartomas with follicular and mesenchymal differentiation

Etiology/Pathogenesis

Multiple lesions are strongly correlated with Birt-Hogg-Dubé syndrome
- High risk of renal cell carcinoma
- Also, pulmonary cysts and pneumothoraces

Clinical Issues

Small papule(s) on face

Microscopic Pathology

FF shows proliferation of thin, anastomosing epithelial cords
Numerous attachments to follicular structures and epidermis
Typically find a central, dilated follicular structure
TD is a stromal-predominant lesion

Clinical examination of a patient with Birt-Hogg-Dubé syndrome shows numerous small, flesh-colored papules on the lateral cheek and neck

. (Courtesy J. Wu, MD.)

Fibrofolliculoma shows a central dilated (cystic) follicular structure with keratin debris. There are multiple thin, radiating epithelial strands attached to the overlying epidermis

TERMINOLOGY

Abbreviations

Fibrofolliculoma (FF)
Trichodiscoma (TD)

Synonyms

Mantleoma (likely fibrofolliculoma variant with sebaceous differentiation)

Definitions

Closely related hamartomatous proliferations with follicular and mesenchymal differentiation
Trichodiscoma likely represents a late stage in evolution of fibrofolliculoma showing stromal predominance

ETIOLOGY/PATHOGENESIS

Genetic Syndrome