Faculty Bibliography

The lunula is the semi-lunar shaped area seen at the proximal aspect of the nail unit. It is the most distal aspect of the nail matrix that can be visualized through the transparent nail plate. The term red lunula describes erythema that partially or completely replaces the normal white color of the lunula. Red lunulae have been associated with a number of dermatologic and systemic conditions. However, the etiology and histopathology of the red lunula have not been characterized. We report a case of red lunulae of the fingernails in an adult male. Histopathologic examination revealed an increased density of benign-appearing and mildly dilated vascular channels present in the superficial papillary dermis of the nail matrix. To our knowledge, this is the first report of distinct pathologic findings seen on histologic examination of a red lunula. The increased vascularity of the lunula seen microscopically correlates with the clinically observed red color. These findings raise the possibility that systemic or local factors are responsible for angiogenesis within the nail unit in disorders associated with the red lunula.

Onychocytic matricoma is a newly described matrical tumor of the nail unit that clinically presents with localized thickening of the nail plate and melanonychia and represents a benign acanthoma of onychocytes. Onychocytic matricoma can be classified according to its histopathologic type (acanthotic, papillomatous or keratogenous with retarded maturation) and pigmentation (pigmented, melanocytic or non-pigmented). However, there are no published reports of non-pigmented onychocytic matricoma. We report a case of hypopigmented onychocytic matricoma that presented with a thickened nail plate, xanthonychia and histopathologic features of acanthosis, prekeratogenous zone and keratogenous zone cells forming pseudosquamous eddies, and minimal pigmentation with Fontana staining. We also provide detailed clinical, intraoperative and histopathologic correlations of this rare tumor. Both clinicians and dermatopathologists should be aware that onychocytic matricoma can present with xanthonychia, thickening of the nail plate and mimic an onychomatricoma.

Onychotillomania represents an unusual dermatosis affecting the nail unit. The term refers to 'neurotic picking at a nail until it is permanently altered'. It can be difficult for dermatologists to diagnose, as typically patients will deny the self-destructive behavior and the clinical features may mimic other inflammatory conditions affecting the nail unit. Aside from the difficulty in establishing the diagnosis clinically, the histopathologic features of onychotillomania are nonspecific. With this limited knowledge, dermatopathologists could have difficulty in correlating the clinical and histopathologic features and determining the correct diagnosis. Establishing the diagnosis is critical, as onychotillomania is sometimes associated with major depression and obsessive-compulsive disorder, and can be a clue to uncovering these debilitating psychiatric disorders. Here we present two cases of onychotillomania and emphasize the clinical-pathological confrontation necessary to secure the diagnosis.

We report a case of a solitary infantile myofibroma masquerading as an ulcerated infantile hemangioma. Infantile myofibroma is a rare soft tissue tumor that has a good prognosis in the solitary form. It may be difficult to distinguish clinically from more common tumors of infancy such as an infantile hemangioma or from other rare entities and therefore requires a biopsy for definitive diagnosis.