Clinicopathological Profile of Childhood Onset Cutaneous Mastocytosis from a Tertiary Care Center in South India

Abstract

Background: Mastocytosis is characterized by clonal proliferation of mast cells in various organs and can have isolated cutaneous or systemic involvement. Childhood-onset mastocytosis (COM) is usually cutaneous and regresses spontaneously, while adult-onset mastocytosis (AOM) is often persistent with systemic involvement. There is limited data on COM from India. Objective: To elucidate the clinicopathological profile of COM. Methods: We conducted a retrospective chart review of all the patients with histologically proven COM (≤16 years), presenting over 11 years (January 2009 to December 2019) to the Dermatology Department. We compiled the demographic data, clinical characteristics (morphology, extent, distribution), laboratory investigations, histopathology findings, imaging (ultrasound abdomen), c-KIT mutation results, where available, and other associated abnormalities, and grouped them according to the WHO classification for mastocytosis. Results: Among the 66 patients with COM (M: F–1.6:1), 89.4% had onset before 2 years of age. The subtypes were: maculopapular cutaneous mastocytosis (MPCM: 44, 66.7%); mastocytoma of the skin (MOS: 19, 28.8%); diffuse cutaneous mastocytosis (DCM: 2, 3%) and indolent systemic mastocytosis (ISM: 1, 1.5%). Blistering was observed in 29 (43.9%) and Darier sign was elicited in 47 (71.2%) patients. Serum tryptase was elevated in 9/21 (42.9%) patients, but none had systemic mastocytosis. Three patients had c-KIT mutations (two in exon 8 and one in exon 17). Most patients were managed symptomatically and the patient with ISM improved with imatinib. Conclusion: MPCM is the most common variant of COM and most patients had a disease onset before 2 years. Overall, COM had a good prognosis with rare systemic involvement, mitigating the need for extensive evaluation routinely in children.

Characteristics of an ethnically diverse cohort of children with pediatric cutaneous mastocytosis: One institution's experience

“…Mastocytoma was the most frequent type of PCM found in our cohort (64.7%), without any specific demographic predisposition. Although many of the available studies report that MPCP is usually the most common phenotype, 2,3,5,6 our findings are similar to the results of an Italian study where out of 133 children with PCM, mastocytoma was the main phenotype (53.4%) 9 . These reports highlight the heterogeneity of PCM among different cohorts.…”

“…Pediatric cutaneous mastocytosis (PCM) is classified as maculopapular cutaneous mastocytosis (MPCM), formerly known as urticaria pigmentosa, diffuse cutaneous mastocytosis (DCM), and mastocytoma. The disease typically appears before the age of 2 in a majority of cases, with a slight male predominance 1–3 . While systemic involvement is infrequent, this can occur, and factors like serum tryptase levels and the extent of skin involvement could be predictors 1,2 .…”

“…The disease typically appears before the age of 2 in a majority of cases, with a slight male predominance 1–3 . While systemic involvement is infrequent, this can occur, and factors like serum tryptase levels and the extent of skin involvement could be predictors 1,2 . It is not known if any demographic features are associated with systemic symptoms.…”

Updates in diagnosis and management of paediatric mastocytosis

“…DCM is the least common and most severe presentation of cutaneous mastocytosis affecting around 5-13% of childhood cutaneous mastocytosis characterized by extensive cutaneous mast cell burden [16]. In the majority of cases, DCM presents with erythroderma, dermatographism and pachydermia (thickened skin) with occasional haemorrhagic bullae [15,18]. DCM may lead to severe mast cell mediator-induced symptoms, including flushing, pruritus, blistering, hypotension and anaphylaxis.…”

“…DCM may lead to severe mast cell mediator-induced symptoms, including flushing, pruritus, blistering, hypotension and anaphylaxis. Patients typically have increased serum tryptase levels, which declines over time and correlates with symptomatic improvement [18]. It is unclear as to what proportion of patients initially diagnosed with DCM have systemic mastocytosis.…”