Extranodal NK/T-cell lymphoma nasal type mimicking pyoderma gangrenosum.

The new World Health Organization / European Organization for Research and Treatment of Cancer (WHO-EORTC) consensus classification for cutaneous lympho-mas recognizes two main groups of CD56 + lymphomas: extranodal natural killer (NK)/T-cell lymphoma nasal type, and CD56+ haematodermic neoplasm (formerly known as blastic NK cell lymphoma (1). NK/T-cell lymphoma nasal type is the most common lymphoma type among primary lymphomas of the nasal cavity (2). It presents clinically as a nasal mass and may involve the skin secondarily, where it often presents as a mid-facial destructive tumour or as multiple distant erythematous nodules, which can evolve to ulceration (3). There is a strong association with Epstein-Barr virus (4). We report here a patient with an extranodal NK/T-cell lymphoma nasal type with cutaneous involvement, in which the clinical presentation mimicked pyoderma gangrenosum. A 73-year-old Caucasian man was admitted due to a 3-week history of malaise, fever, swelling of the left eyelids and proptosis of the left eye. Laboratory tests revealed a white cell count of 16,000 with 70% of neutrophils, haemoglobin 10.1 g/dl, MCV-83 fl, platelets 59,000/mm 3. A facial computed tomography (CT)-scan showed inflammation of the left maxillary sinus and a mass on the medial wall of the left orbit. A diagnosis of sinusitis and left orbital abscess was made. The patient received several courses of intravenous antibiotics without improving. Ten days after admission, a dermatology referral was made due to a cutaneous lesion localized on the anterior abdominal wall, presenting since the beginning of the clinical picture. Examination revealed a 6 × 3 cm indurate purplish plaque, with several haemorrhagic bulla on the periphery and a necrotic crust on the centre, localized on the upper abdominal wall (Fig. 1a). On the upper chest and back multiple erythematous circinate lesions, slightly infiltrated, were found (Fig. 1b). Clinically, he was thought to have a neutrophilic dermatosis coexisting with pyoderma gangrenosum and Sweet's syndrome. Two skin biopsies were taken from morphologically different lesions, one on the upper abdominal wall (purplish plaque with bullae) and the other on the upper thoracic wall (erythematous infiltrated plaque). Histology of the first biopsy showed a prominent ne-crotic epidermal necrosis, the epidermis appeared detached from the dermis at some points; the second biopsy evidenced marked basal cell vacuolar changes with necrotic keratinocytes. Both biopsies showed the dermis diffusely infiltrated by a mixture of small-to medium-sized, pleomorphic atypical lymphoid cells with prominent dermal necrosis, acquiring occasionally an angiocentric …