Mastocytosis

Abstract

Mastocytosis is a disorder of abnormal mast cell proliferation, with clinical features that include flushing, pruritus, abdominal pain, diarrhea, hypotension, syncope, and musculoskeletal pain. These features are the result of mast cell mediator release and infiltration into target organs. Patients of all ages may be affected, although in children, manifestations primarily involve the skin. Most patients with systemic disease have a somatically acquired activating mutation in the KIT oncogene. This article discusses the causes and pathogenesis of mastocytosis, with an overview of the clinical features and the approach to diagnosis, evaluation, and therapy in adults and pediatric patients.

Keywords: Bone marrow; KIT; Mast cell; Mastocytosis; Skin; Urticaria.

Conflict of interest statement

Authors state no conflict of interest.

Published by Elsevier Inc.

Figures

Figure 1. Urticaria Pigmentosa in an adult

A) Typical maculo-papular lesions of uniform size, generally

Figure 2. Urticaria pigmentosa in a child

Tan papules and thin plaques on this child’s back reflect the larger size of lesions, which may be seen in children in comparison to those in adults. Lesions on sun-exposed areas such as the extremities tend to appear less active as in this case.

Figure 3. Diffuse cutaneous mastocytosis

A) Diffuse dermal thickening, pachydermic flesh colored lesions and B) Bullous eruption in a child.

Figure 3. Diffuse cutaneous mastocytosis

A) Diffuse dermal thickening, pachydermic flesh colored lesions and B) Bullous eruption in a child.

Figure 4. Solitary mastocytoma on the foot sole of a child

A flat red to tan nodule with clearly defined border.

Figure 5. Histopathology of Urticaria Pigmentosa from a 7 yr old

Clustering of normal and spindle-shaped mast cells in papillary dermis and extending into the reticular dermis. The tryptase stain highlights perivascular cuffing and interstitial presence of the mast cells. A) Giemsa stain 40X B) Tryptase stain 100X.

Figure 6. Bone marrow histopathology in an adult with Indolent Systemic Mastocytosis

Mast cell aggregates demonstrated by staining with tryptase in A) (40X); and B)highlights the mast cell component of the aggregate and the prominent abnormal spindle-shaped mast cells (100X).