Abstract
The histopathological diagnosis of the child tumour group formed by small dark cells is frequently difficult toestablish. Sometimes the correct diagnosis can not be determined before various imunohistochemical, cytogeneticand molecular genetic techniques have been used.
Paediatric non-Hodgkin's lymphomas belong to this group oftumours. The diagnostic mistake in a ten-years-old boy, previously treated for aggressive fibromatosis for twoyears, is described.
Surprisingly the fourth biopsy proved a quite unusual sclerotic variant of malignant B-celllymphoma. Modified treatment followed by autologous bone marrow transplantation led to complete remissionalready persisting for six years.
By coincidence at the same time the patient's father underwent bone marrowtransplantation because of recurrent malignant lymphogranuloma