Localized eosinophilic (Langerhans' cell) granuloma of the lower lip. A lesion that may cause diagnostic error.

Eosinophilic (Langerhans' cell) granuloma is most common in children and is unusual in the elderly. A cutaneous lesion as the sole manifestation of adult Langerhans' cell histiocytosis is rare. We report an 81-year-old man who presented with a noduloulcerative lesion on the lower lip. A punch biopsy suggested a lymphoepithelioma-like carcinoma. In the absence of immunohistochemistry, the large pale cells with atypical lobular nuclei and patent nucleoli, with an overlying ulceration, were interpreted as carcinoma cells. Definitive diagnosis was established after complete resection of the lesion aided with the use of immunohistochemistry. The proliferating cells were S100, CD1a and CD207 (langerin) positive and cytokeratin, epithelial membrane antigen, CD15, CD30, melan A and carcinoembryonic antigen negative. To our knowledge, eosinophilic (Langerhans' cell) granuloma of the lip has not been described. The case constituted a diagnostic challenge because of its unusual clinical presentation and its histopathological similarity to certain other benign and malignant entities. Because there was no other organ involved, the patient was treated with complete surgical excision without recurrence or other organ involvement in the 4-month follow-up period. Labial eosinophilic (Langerhans' cell) granuloma should be considered in the histological differential diagnosis in cases with atypical polymorphous infiltrates including large pale cells.