Maculopapular cutaneous mastocytosis in a diverse population

Cutaneous mastocytosis (CM) is most frequently diagnosed in children, as well as in the majority of adults with systemic mastocytosis (SM). Most commonly, both pediatric and adult patients present with the maculopapular cutaneous mastocytosis (MPCM) variant, also known as urticaria pigmentosa (UP) (1). Large polymorphic lesions over trunk, head and extremities tend to occur in childhood-onset CM, and small monomorphic lesions over thigh and trunk, which may also occur in children, predominate in adulthood-onset CM. White, non-Hispanic patients are the predominate population at most centers including the NIH. We thus asked whether the ability to identify MPCM in other groups might differ and confound the clinician from properly identifying and making the diagnosis of CM for patients undergoing evaluation.

In this retrospective examination of the appearance of MPCM in various populations and following informed consent, records of ten patients (three African American, three Hispanic, two White, non-Hispanic and two Asians patients) reported herein were reviewed for race/ethnicity, mastocytosis variant, age at time photographs of lesions were obtained, age of onset of disease, serum tryptase levels and presence of KIT D816V in peripheral blood (PB) (Table). Pediatric patients had onset of CM at birth or during the first year of life and adult patients with CM had ISM (CM/ISM) diagnosed during early to mid-adult years. Of the pediatric patients, one was African American, two were Asians, two were Hispanic and one was White, non-Hispanic. Of the adult patients, two patients were African American, one patient was Hispanic, and one patient was White, non-Hispanic. Pediatric patients had tryptase levels ranging from 2.2 to 218.0 ng/ml. Adult patients had tryptase levels ranging from 15.8 to 218.0 ng/ml. One pediatric patient with CM and probable ISM (patient #7) was positive for KIT D816V as well as the pediatric patient diagnosed with ISM (patient #4); of the remaining four pediatric patients with CM, one was negative and three were not studied for the mutation. All adult patients with CM/ISM were positive for KIT D816V.

Table 1.

Demographic and Clinical Data of Patient Population

Patient	Race/Ethnicity*	Variant#	Age in photo (years)	Age of onset	Pertinent medical history**	Serum Tryptase (ng/ml)	KIT D816V mutation‡
1	AA	ISM	60	49 years	AP, D, da, DZ, P, SB	90.0	+
2	AA	ISM	38	32 years	P	15.8	+
3	AA	CM	5	6 months	AP, U, V	5.4	NA
4	W	ISM	9	Birth	AP, DA, F, FA, H, P, U	218.0	+
5	W	ISM	28	26 years	AP, D, DA, F, P,	218.0	+
6	H	CM	6	Birth	AP, B, BP, DA, F, FA, N, P, SB, U	4.6	NA
7	H	CM/pISM	1	Birth	FA, P, U	19.4	+
8	H	ISM	69	59 years	H	30.4	+
9	A	CM	.75	3 weeks	B, F, P	63.9	NA
10	A	CM	2	3 months	FT, Hy, P, U	2.2	-

(designated per NIH IRB guidelines).

^#ISM, Indolent Systemic Mastocytosis diagnosed by WHO criteria; CM, Cutaneous Mastocytosis: Maculopapular Cutaneous Mastocytosis variant (MPCM) diagnosed by WHO definition of cutaneous mastocytosis; pISM-probable ISM.

^**AP, Abdominal pain; B, Blisters; BP, Bone pain; D, Diarrhea; DA, Drug Allergies; DZ, Dizziness; F, Flushing; FA, Food Allergies; FT, Fatigue; H, Hypotension; Hy, Hyperpigmentation; N, Nausea; P, Pruritus; SB, Shortness of Breath; U, Urticaria; V, Vomiting. NA, Not Available.

^‡Peripheral blood KIT D816V.

^*AA African American; W, White, non-Hispanic; H, Hispanic; A; Asian

As shown in Figures 1A–B, adult African American patients and the adult Hispanic patient (IC) had monomorphic lesions over the trunk similar to the White, non-Hispanic patient (ID) , which were easily identifiable. Pediatric African American and Hispanic patients (Figs. 2A–B) also exhibited easily identifiable monomorphic lesions over the trunk. Two Asian patients, (Figs. 2C–D) both demonstrate a consistent pattern of skin lesions, although subtler in one and nodular lesions in the other. One Hispanic patient (Fig. 2E) exhibited polymorphic small and larger lesions, which were confluent in some areas. All lesions were characteristically similar to the White, non-Hispanic pediatric patient (Fig. 2F).

Fig 1.

Cutaneous lesions in adult - onset mastocytosis. A. African American male. B. African American female. C. Hispanic male. D. White, non-Hispanic male. All lesions are monomorphic.

Fig 2.

Cutaneous lesions in pediatric-onset mastocytosis. A. African American male. B. Hispanic male. C. Asian male. D. Asian female. E. Hispanic female. F. White, non-Hispanic female. A-D and F are monomorphic, E is polymorphic.

These images thus demonstrate that the macroscopic features of CM lesions in various populations should not, in general, prevent proper identification and diagnosis of MPCM.