A Retrospective Review of Undifferentiated Malignancy in Childhood

Abstract

We reviewed the experience of children with "undifferentiated" cancer at The Children's Hospital of Pittsburgh (CHP) from 1971 through 1987. Of 2,095 patients 0-18 years old with diagnoses during that time of any cancer, the initial CHP pathology report rendered a diagnosis in 22 children (1.1%) of "undifferentiated malignancy" or "malignant tumor" (15 cases), "undifferentiated carcinoma" (two cases) or "anaplastic tumor or carcinoma" not otherwise specified (five cases). A review of pathologic findings using current methods and immunostaining led to the assignment of a specific diagnosis in 15 of the 20 cases so studied. Thus, the incidence of undifferentiated cancer by current criteria was reduced to no more than 0.23%. Two of the five tumors for which an alternative diagnosis could not be established were described as "rhabdoid," but because it is not clear that these tumors fit into a single category they were still considered to be undifferentiated. Clinical features and management of the 22 cases including the five persistently diagnosed as undifferentiated malignancy were heterogeneous. In the face of reassigned diagnoses, a number of patients would likely have received different chemotherapy as well as radiation. Nonetheless, seven patients with malignancy show no evidence of disease (NED), including several whose therapy, given the current best diagnosis, would not be considered to have been optimal. We recommend that for patients undergoing biopsy of a tumor, sufficient material be obtained for extensive pathologic evaluation. In this way, the diagnosis of undifferentiated malignancy in children can be almost eliminated.(ABSTRACT TRUNCATED AT 250 WORDS)