Challenging differential diagnosis, Rare disease
Filipe Jaeger, Hermínia Marques Capistrano, Wagner Henriques de Castro, Patrícia Carlos Caldeira, Maria Auxiliadora Vieira do Carmo, Ricardo Alves de Mesquita, Maria Cássia Ferreira de Aguiar
Department of Oral Pathology and Surgery, School of Dentistry, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
Am J Case Rep 2015; 16:844-848
Spindle cell lipoma (SCL) is an uncommon and histologically distinct variant of lipoma. It usually occurs as a solitary, subcutaneous, and well-circumscribed lesion in the posterior neck, shoulders, and back of older men. SCL of the oral cavity is rare. We present the clinical-pathologic features of the third case of SCL located on the hard palate and discuss the histological differential diagnosis with other fusiform neoplasms.
CASE REPORT: A 56-year-old man was evaluated for an asymptomatic swelling on the right side of the hard palate. The intraoral examination showed a 25×20 mm sessile and circumscribed tumor, underlying an apparently healthy mucosa of normal color. The lesion revealed a floating consistency during palpation. Excisional biopsy was carried out based on a clinical diagnosis of lipoma or a benign minor salivary gland tumor. The histopathology demonstrated a well-circumscribed but unencapsulated proliferation of bland spindle cells admixed with mature adipocytes in a collagenous/myxoid stroma. The spindle cells were uniform, exhibiting elongated nuclei and narrow cytoplasmic processes without atypia. They were positive to CD34 and negative to factor VIII, alpha-smooth muscle actin, S100, cytokeratin, and actin. Mitotic activity was low, as confirmed by Ki-67 immunostaining. No lipoblastic activity was found. The diagnosis of SCL was therefore established.
CONCLUSIONS: Oral spindle cell lipoma is a rare benign lipomatous tumor. The histologic picture shows a range of variations and the observation of morphological features is important to distinguish this lesion from other fusiform tumors. Immunohistochemistry should be helpful in this differentiation.
Keywords: Diagnosis, Differential, Biopsy, Lipoma - diagnosis, Mouth Mucosa - pathology, Mouth Neoplasms - diagnosis