Case for diagnosis
A 53-year-old Caucasian male was referred to our Department due to an asymptomatic\nerythematous plaque on the left buttock evolving for 5 months and with progressive\nincrease. On physical examination, an erythematous-brownish plaque was observed with a\nraised erythematous-red border and areas of erosion (). There were no other signs or symptoms. A biopsy showed\nhyperkeratosis, acanthosis and spongiosis, as well as epidermotropism of isolated and\ngrouped large-sized atypical lymphocytes with pale halos, also present in the upper\ndermis. Immunohistochemistry revealed positive staining of these cells for CD3 and CD8\n() without staining for CD4, CD30 and\nCD56, consistent with the diagnosis of pagetoid reticulosis (PR) - Woringer-Kolopp\ndisease (WKD). The microbiological examinations of the skin were negative. Three weeks\nlater the patient developed several nummular erythematous lesions with a scaling border\nscattered on the legs (). We repeated the\nbiopsy, which revealed identical findings plus positive staining for CD45 and a\nproliferative index of 90% (Ki67). Subsequently, these lesions increased in size,\nassuming the shape of the original plaque and a diagnosis of Ketron-Goodman disease\n(KGD) was established. The patient started treatment once daily with betamethasone\ndipropionate ointment and, simultaneously, was referred to the haematological outpatient\ndepartment to exclude systemic involvement. All tests were normal, including the\nperipheral blood immunophenotyping, the bone marrow biopsy and the\nthoracoabdomino-pelvic computed tomography scans. After 4 months of therapy with topical\nbetamethasone dipropionate, all the lesions cleared, with the exception of a single\nlesion on the left foot, which was submitted to radiotherapy and resolved in 4 months.\nIn a follow-up over 2 years the patient has remained free of signs and symptoms.