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Mastocytoma in Infant/Neonate
Other Resources UpToDate PubMed

Mastocytoma in Infant/Neonate

Contributors: Nnenna Agim MD, FAAD, Susan Burgin MD
Other Resources UpToDate PubMed


A mastocytoma is a form of cutaneous mastocytosis that may be present at birth or may develop in infancy. Cutaneous mastocytosis is a clonal disorder of mast cell accumulation. According to the World Health Organization (WHO) classification, cutaneous and systemic forms of mastocytosis are distinguished.

About 80% of pediatric mastocytosis cases present with cutaneous involvement, and 60% of all pediatric cutaneous mastocytosis cases present at birth.

Mastocytomas account for 10%-15% of pediatric cutaneous mastocytosis. Mastocytomas present with one or a few (up to 3) papules, plaques, or nodules (a diagnosis of urticaria pigmentosa is made if there are 4 or more lesions). The lesions may be pruritic and may swell spontaneously or after thermal, mechanical, or chemical stimulation. Thermal stimulation can occur after a bath, emotional stress, physical exertion, or with change in seasons. Mechanical stimulation can occur during surgery or following administration of vaccines. Chemical stimulation may be with foods or with topical or oral medication.

Mild systemic signs and symptoms may include flushing, bone pain, and headache. Hypotension / anaphylaxis, esophageal irritation, intestinal bleeding, and lymphadenopathy are less common with solitary mastocytomas but more frequently accompany other forms of cutaneous mastocytosis, such as urticaria pigmentosa and diffuse cutaneous mastocytosis.


D47.01 – Cutaneous mastocytosis

404171008 – Mastocytoma

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Differential Diagnosis & Pitfalls

  • Congenital melanocytic nevus
  • Café au lait spot
  • Spitz nevus
  • Juvenile xanthogranuloma
  • Arthropod bite or sting
  • Staphylococcal scalded skin syndrome may be mistaken for mastocytoma if only the blisters are seen.

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Last Reviewed:02/24/2020
Last Updated:04/02/2020
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Mastocytoma in Infant/Neonate
A medical illustration showing key findings of Mastocytoma : Darier's sign positive, Neck, Trunk, Pruritus
Clinical image of Mastocytoma - imageId=729955. Click to open in gallery.  caption: 'An edematous pink plaque with a peau d'orange appearance on the flank.'
An edematous pink plaque with a peau d'orange appearance on the flank.
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