Leonine facies in an old man

Discussion

Leonine facies is a face that resembles that of a lion. It can be seen in multiple conditions that include both infective and non-infective. It has been classically described for lepromatous leprosy. Apart from leprosy, leonine facies can be seen in actinic reticuloid, mycosis fungoides, leishmaniasis, scleromyxedema, and lymphoma. Though these entities may have a common clinical feature, i.e. leonine appearance of face, they have very distinctive histopathological findings which are diagnostic.

Trichoepithelioma also known as epithelioma adenoides cysticum was first described by Brooke and Fordyce in 1892. It is a benign tumor of folliculosebaceous origin. ^[1] Trichoepithelioma can occur in two forms: solitary and multiple familial trichoepithelioma.

Multiple familial trichoepithelioma is transmitted as an autosomal dominant trait. Onset is usually seen in the childhood as asymptomatic skin-colored papules over the face predominantly affecting nasolabial folds and central part of the face. Lesions may also appear on the neck and trunk. Lesions increase in size with the age, may coalesce to form large lesions, occasionally giving rise to a leonine appearance to the face. Trichoepitheliomas can be one of the multiple skin appendageal tumors that are seen in Brooke-Spiegler syndrome which commonly include cylindroma and spiradenoma. Malignant transformation of trichoepithelioma is very rare. ^[2]

Multiple familial trichoepithelioma-1 (MFT1) and multiple familial trichoepithelioma-2 (MFT2) have been reported to have a similar clinical picture but have mutations in the CYLD gene at different loci, on chromosome 16q12-q13 and 9p21, respectively. ^[3],[4] Brooke-Spiegler syndrome, familial cylindromatosis and MFT1 have same genotypic mutation but different clinical manifestations and as they can occur in the same patient or in different patients within a single family; some authors consider them as different phenotypic expression of a single disease entity. ^[5],[6]

On histopathology trichoepithelioma shows proliferation of basaloid cells in the dermis in various patterns of which cribriform or sieve like is the most common [Figure - 2] and [Figure - 3]. Infundibulocystic structures and germ and papillae structures are commonly seen [Figure - 4]. Occasionally calcification can be seen. At times it may be difficult to distinguish trichoepithelioma from basal cell carcinoma.

Solitary trichoepithelioma can be excised surgically while multiple trichoepitheliomas are difficult to manage. Laser ablation, cryosurgery, and electrocautery have been found useful with variable success. ^{[7],[8],[9],[10]}