Tender, subcutaneous nodules in an unwell patient

A 47-year-old woman of Trinidadian origin presented to a dermatology department with a 12-month history of tender, red, subcutaneous nodules on her legs and torso (Fig. 1). She reported weight loss (20 kg over 12 months), lethargy and night sweats. An initial skin biopsy suggested a lobular panniculitis. Computed tomography (CT) of the chest showed moderate hilar lymphadenopathy with calcification. Despite negative results from a Mantoux test, the respiratory physicians considered that tuberculosis could not be excluded, and started the patient on antituberculosis treatment (rifampicin, isoniazid and pyrazinamide combination; Rifater; Sanofi UK, Guildford, Surrey, UK). However, the patient continued to develop nodules. Investigations identified microcytic anaemia (haemoglobin 8 g ⁄ dL; normal range 11.5–16.0 g ⁄ dL), and greatly increased levels of inflammatory markers [C-reactive protein 65 mg ⁄ L (normal range <10 mg ⁄ L), erythrocyte sedimentation rate 111 mm ⁄ h (0–20 mm ⁄ h), lactate dehydrogenase 616 (10–250 U ⁄ L), ferritin 2668 lg ⁄ L (15–300 lg ⁄ L)]. A bone-marrow trephine biopsy showed reactive changes only. An 8-week trial of oral corticosteroids (prednisolone 30 mg daily) resulted in a modest, unsustained improvement. The patient was then referred to our dermatology department. On examination, there were widespread, erythematous, indurated, subcutaneous nodules, and the patient had pyrexia (39.9 C), hepatomegaly and lymphadenopathy. In addition to the existing anaemia, investigations now identified lymphopenia (0.3 · 10 ⁄ L; 1.5–4 · 10 ⁄ L) and monocytopenia (0.1 · 10 ⁄ L; 0–0.8 · 10 ⁄ L). Results of tests for human immunodeficiency virus 1 and 2 and human T-cell lymphotropic virus 1 and 2 were negative. A new incisional skin biopsy was taken from an abdominal nodule.