Primary mediastinal (thymic) B-cell lymphoma presenting as cutaneous vasculitis.

Cutaneous small vessel vasculitis is a severe neutrophilic vascular inflammation mediated by immune complexes that involves the dermal postcapillary venules. Neoplasms represent 2-5% of all causes of secondary cutaneous vasculitis. We present a case of a 52-year-old man who was admitted due to a 10-day history of respiratory symptoms and myalgia. From the third day of symptoms onwards, the patient noticed the appearance of cutaneous lesions in the lower limbs with palpable purpura and erythematous papules. Additionally, he reported of asthenia, anorexia and weight loss during the prior month. Chest radiography showed an enlarged mediastinum and thoracoabdominal-pelvic CT scan revealed a bulky left hilar mass. Biopsy of the left superior lobar bronchus' mucosa allowed for the histological diagnosis of diffuse large B-cell lymphoma (DLBL) of the thymus. The patient received symptomatic treatment with improvement of the purpuric lesions and a multiagent chemotherapy regimen was initiated.