Cutaneous Mastocytoma : Differential

Comments:
Differential Diagnosis of Solitary Cutaneous Mastocytoma: The differential diagnosis of solitary cutaneous mastocytoma includes persistent insect bite reaction and congenital or early-onset melanocytic nevus. If there are more than 3-4 lesions, a diagnosis of urticaria pigmentosa should be considered.

This image shows a compact cluster of uniform mast cells in dermis in a case of solitary cutaneous mastocytoma. Note the faint granules in the cytoplasm. These show metachromatic staining with Giemsa or Toluidine blue stains.

Image courtesy of: Miguel Reyes-Mugica, MD, Chief of Pathology, Univ. of Pittsburgh Children's Hospital, Pittsburgh, Pennsylvania, USA.