Hemangiopericytoma-Like Dermatofibroma With Mast CellsAneiros-Fernandez, Jose MD*; Arias-Santiago, Salvador MD†; Espiñeira-Carmona, Maria Jose MD†; Caba-Molina, Mercedes MD*; Fernandez-Pugnaire, Maria Antonia MD†; O'Valle, Francisco MD, PhD*; del Moral, Raimundo Garcia MD, PhD*; Aneiros-Cachaza, Jose MD, PhD*The American Journal of Dermatopathology: August 2011 - Volume 33 - Issue 6 - p e74-e76 doi: 10.1097/DAD.0b013e31821e1a47 Brief Report Abstract Author Information We report an unusual case of hemangiopericytoma-like dermatofibroma in the right shoulder of an 82-year-old patient with a well-defined nodular growth located in the dermis. Microscopic study revealed a band of haphazardly arranged cells with a vascular component of gaping, simple, endothelial-lined vascular structures with intervening postcapillary venules and capillary-sized slit-like “staghorn” vascular channels filled with erythrocytes; abundant mast cells were also observed. The neoplasm cells were positive for CD68 and Factor XIIIA and negative for CD34. Few data have been published on the presence of abundant mast cells (tryptase and CD117 positive) in these neoplasm. The differential diagnosis of this entity should consider other spindle cell neoplasm, including hemangiopericytoma/solitary fibrous tumor, dermatofibrosarcoma protuberans, myopericytoma, angioleiomyoma, amelanotic melanoma, pecoma, and benign and malignant peripheral nerve tumors. We present an infrequent case of dermatofibroma with a vascular pattern resembling hemangiopericytoma and the presence of abundant mast cells, which may be responsible for this vascular component. From the Departments of *Pathology; and †Dermatology, University Hospital, Granada, Spain. The authors have no Funding or conflict of interest to declare. All authors approve the submission. All authors have participated sufficiently to take public responsibility for appropriate portions of the work. Reprints: Dr. Jose Aneiros-Fernandez, MD, Department of Pathology, University Hospital, Granada, Spain, Avd. Madrid S/N, CP: 18012 (e-mail: firstname.lastname@example.org). © 2011 Lippincott Williams & Wilkins, Inc.