Telangiectasia macularis eruptiva perstans with systemic involvement: a case report

Abstract Background: Telangiectasia macularis eruptiva perstans (TMEP) is a rare form of cutaneous mastocytosis which usually presents as ill-defined reddish brown telangiectatic macules. Although cutaneous mastocytosis rarely presents with systemic involvement, almost half of patients with TMEP demonstrate systemic mastocytosis. Currently, there is no guidance surrounding systemic testing in patients with TMEP. Case presentation: A 50-year-old Caucasian male was referred to the Clinical Immunology and Allergy clinic with a history of a rash. He initially presented to hospital 12 years prior with group A beta hemolytic streptococcus bacteremia treated with multiple different antibiotics. One week following discharge, he developed erythematous brown spots on his right leg which were flat, non-pruritic and not painful. The rash later expanded to his trunk and extremities. A skin biopsy performed two years prior to referral to our clinic demonstrated telangiectasia macularis eruptiva perstans. The CD117 immunohistochemical stain showed increased perivascular and interstitial mast cells in the superficial dermis. Darier’s sign was negative on physical examination, and venom testing was also negative. Although he had no symptoms of systemic involvement, a serum tryptase was elevated at 47.6 ng/mL in the context of normal kidney and liver function. A skeletal survey was normal and an abdominal ultrasound ruled-out splenomegaly. Bone marrow biopsy demonstrated a mild increase in paratrabecular and perivascular atypical mast cells, in keeping with systemic mastocytosis.Conclusions: Unlike other forms of cutaneous mastocytosis, patients with TMEP have a high likelihood of an underlying systemic mast cell disorder. Therefore, any patient presenting with characteristic skin findings should be investigated as having a cutaneous manifestation of systemic mastocytosis. This case demonstrates the utility of serum tryptase, and its role in triggering additional investigations and guiding appropriate therapy.