Unilateral telangiectasia macularis eruptiva perstans: A rare case of adult-onset cutaneous mastocytosis

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Here, we report a case of a 35-year-old woman who presented to the dermatology outpatient clinic with complaints of reddish to slightly hyperpigmented lesions over the left flank region for the past 3 months. The lesions were asymptomatic and initially involved small areas but became more noticeable over time as they increased in size and color intensity. She reported episodic flushing and palpitations but denied other systemic symptoms such as abdominal pain, diarrhea, syncope, itching, wheal, or anaphylaxis. On clinical examination, we observed diffuse erythematous macules with telangiectasias distributed over the left side of the abdomen [Figure 1a]. The lesions exhibited a positive Darier’s sign, characterized by a wheal flare response upon rubbing [Figure 1b]. No hepatosplenomegaly, lymphadenopathy, or other systemic manifestations were noted. Clinical differentials included telangiectasia macularis eruptive perstans, poikiloderma of civatte, nevoid/segmental telangiectasia, angioma serpiginosum, livedo racemosa, livedo reticularis, cutis marmorata telangiectatica congenita, and erythema ab igne.

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Figure 1

(a): Diffuse erythematous macules with telangiectasias distributed over the left side of the abdomen; (b): The lesions exhibiting a positive Darier’s sign.

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A dermoscopic examination revealed a diffuse, reddish background erythema, a network of telangiectatic vessels, a patchy pigment network, and yellowish, pale areas [Figure 2]. Investigations included a complete blood count, liver function tests, and kidney function tests, as well as serum tryptase levels, which were within normal limits. Histopathology revealed stratified squamous epithelium with an underlying papillary dermis, characterized by a few dilated capillaries and perivascular mast cells, which are immunoreactive for CD117 [Figure 3]. Based on clinical, dermoscopic, and histopathological findings, a diagnosis of telangiectasia macularis eruptiva perstans (TMEP) was confirmed. Given the absence of systemic involvement, the patient was managed symptomatically. Table 1^[1-3] depicts the dermoscopic findings of the possible differentials.

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Figure 2:

Dermoscopy showing diffuse, reddish background erythema, a network of telangiectatic vessels, a patchy pigment network, and yellowish, pale areas (DL4, polarized, 10x).

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Figure 3:

Histopathological examination revealing (a): Scanner view (H&E, 4x); (b): stratified squamous epithelium with an underlying papillary dermis characterized by a few dilated capillaries and perivascular mast cells (H&E, 10x); (c): papillary dermis characterized by a few dilated capillaries and perivascular mast cells (H&E,40x); and (d): immunohistochemical examination showing immunoreactivity for CD117. H&E: Hematoxylin and eosin.

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Mastocytosis refers to a heterogeneous group of disorders characterized by abnormal mast cell accumulation in tissues.^[1] Cutaneous mastocytosis is primarily seen in children but may persist into adulthood or present de novo.^[1,4] TMEP, first described by Parkes-Weber in 1930, is an uncommon form of cutaneous mastocytosis that predominantly affects adults.^[4] It is a rare form of adult-onset cutaneous mastocytosis that requires a high index of suspicion for diagnosis. TMEP primarily affects adults and is clinically characterized by persistent telangiectatic macules caused by mast cell infiltration in the dermis, typically appearing on the trunk and extremities.^[1,4]

Flushing, as seen in our patient, occurs due to the release of mast cell mediators, particularly histamine. Unlike urticaria pigmentosa or maculopapular cutaneous mastocytosis, which is more common in pediatric mastocytosis, TMEP predominantly affects adults and may, in some cases (around 50%), suggest systemic involvement. Although our patient showed no signs of systemic disease, regular monitoring is crucial to detect any potential progression.^[5]

Diagnosis of TMEP requires a combination of clinical, dermoscopic, and histopathological evaluation. A hallmark clinical feature is a positive Darier’s sign, which was observed in our case. Histologically, TMEP is marked by a mild mononuclear infiltrate with a notable concentration of mast cells surrounding the superficial venous plexus capillaries. On average, the number of mast cells is increased 4-8 fold in the lesional dermis of patients with cutaneous mastocytes compared with normal skin. Similar changes were observed in histopathology. Special stains, such as Giemsa or toluidine blue, are instrumental in identifying mast cells by highlighting their metachromatic cytoplasmic granules, making them valuable in diagnostic evaluation.^[1,4]

Histopathological examination remains the definitive method for confirmation, revealing perivascular mast cell infiltration that stains positively for CD117. While serum tryptase levels are frequently within normal limits in cutaneous mastocytosis, they serve as a crucial biomarker for potential systemic involvement.^[2]

Dermoscopy aids in distinguishing TMEP from other vascular dermatoses, revealing telangiectatic vessels, a diffuse red-brown background, and yellowish areas suggestive of mast cell accumulation.^[1,3]

Early recognition and appropriate management can significantly improve the patient’s quality of life. Management strategies include avoidance of known triggers such as alcohol, non-steroidal anti-inflammatory drugs, temperature extremes, H1-antihistamines (e.g., cetirizine or fexofenadine) for symptomatic relief of flushing, and periodic monitoring for systemic involvement. Treatment options such as psoralen and ultraviolet A therapy, intense pulsed light, or leukotriene inhibitors may be considered for refractory cases.^[3,6] In our patient, reassurance and antihistamines were initiated, with plans for long-term follow-up.

This case underscores the significance of recognizing TMEP in adult patients and utilizing dermoscopy to facilitate accurate diagnosis. E-arly identification and effective management are crucial to enhancing patient outcomes and quality of life.