Pseudoxanthomatous mastocytosis

A 50‐year‐old woman presented with itchy, multiple, flat, yellowish, waxy papules and plaques diffusely involving her face, trunk, and upper extremities for 5 years ( Fig. 1 ). Itching was moderate to severe in intensity and was episodic, without any identifiable aggravating or relieving factors. On rubbing the lesions with a blunt object erythema was elicited. Her ophthalmological examination was normal. Her complete hemogram was normal along with other routine investigations. Patient's slit skin smear for acid‐fast bacilli and rk39 dip‐stick ELISA for post‐kala‐azar dermal leishmaniasis were negative. Ultrasound examination of her abdomen was normal and skeletal survey showed no evidence of bony changes. Histological examination showed diffuse dense infiltrate of numerous mast cells filling up the papillary dermis and most of upper‐ and mid‐reticular dermis. Overlying epidermis showed moderate epidermal hyperplasia and hyperpigmentation. There was sparse scattering of neutrophils within the infiltrate. Extracellular mast cells granules were also seen ( Fig. 2 ). Diagnosis of diffuse cutaneous mastocytosis of pseudoxanthomatous variety was made.

Figure 1 Open in figure viewer PowerPoint Pretreatment photographs of the patient; (a) face; (b) trunk