LANGERHANS CELL HISTIOCYTOSIS MIMICKING MALIGNANCY - A RADIOLOGICAL APPRAISAL

Aims: To analyze the radiologic characteristics, clinical course and l ong-term follow-up of 7 radiologically uncommon pediatric cases of Lan gerhans cell histiocytosis and to identify prognostic factors related to imaging patterns. Methods: The clinical records and complete imagin g data of 75 patients with LCH diagnosed and treated at the National C ancer Institute of Milan between January 1975 and December 1993 were a nalyzed, and 43 cases presenting as unifocal bone lesions were identif ied. The plain film, computed tomography and magnetic resonance charac teristics enabled the identification of 7 radiologically aggressive an d rapidly progressive cases, which were analyzed at presentation and d uring follow-up. Results: Although at disease presentation bone lesion s appeared lytic destructive, rapidly progressive and often involved a djacent soft tissues, after adequate therapy the disease course was in variably benign and led to almost complete restoration of normal struc ture and function. Long-term follow-up confirmed the favorable outcome and lack of disease recurrence in all cases. Conclusions: There is no correlation between radiologically aggressive characteristics and fin al outcome in Langerhans cell histiocytosis. Radiologists and pediatri c oncologists should be acquainted with less common radiologic forms w hich, at presentation, can mimic more ominous diseases. If recognized and adequately treated, monostotic forms almost invariably have a beni gn prognosis.