The detection of occult renal tumors in children by elevated hematocrit on routine complete blood count: a report of two cases.

Wilms' tumor is a renal neoplasm usually found in young children and is rarely seen in teenagers. The production of erythropoietin by these tumors may result in secondary erythrocytosis, which should be reflected in complete blood counts (CBC). A search of the literature for reports of occult Wilms' tumors initially suspected on the basis of erythrocytosis was unrewarding. Two teenagers are reported in whom unexplained erythrocytosis was the initial indication of a Wilms' tumor. In both cases, a previous CBC showed elevations in hemoglobin and hematocrit that might have led to an earlier diagnosis. We conclude that unexplained erythrocytosis should sound the alert for further diagnostic studies to evaluate the possibility of occult renal neoplasia in older children.

Prognostic significance of terminal transferase activity in childhood acute lymphoblastic leukemia: a prospective analysis of 164 patients.

Whether the level of terminal deoxynucleotidyl transferase (TdT) activity in mononuclear cells from bone marrow and peripheral blood has prognostic significance has been analyzed prospectively in 164 children with T and non-T, non-B marked acute lymphoblastic leukemia (ALL). TdT was measured at diagnosis to assess its value as a predictor of duration of remission and length of survival. It was measured repeatedly during remission to assess whether it could predict relapse. Ninety-seven percent of the children achieved a complete remission of their disease, and 40% relapsed during the study. The level of TdT activity in blasts at diagnosis varied 1000-fold from patient to patient. There was no statistically significant relationship between TdT activity in cells at diagnosis and the achievement of complete remission, the duration of remission, or length of survival. TdT activity was significantly increased in the bone marrow of 65% of patients at the time of marrow morphological relapse, but was rarely increased in marrow from patients with isolated testicular or central nervous system relapse. Wide fluctuations in TdT activity were characteristically seen in mononuclear cells from the marrow and peripheral blood of patients with ALL at all stages of their disease. An isolated high value of TdT activity in the bone marrow or peripheral blood cannot be taken as evidence of impending relapse. Quantitative measurements of TdT activity alone on mononuclear cells from bone marrow and peripheral blood are helpful in differential diagnosis, but cannot guide therapy of children with ALL.

Adenosine deaminase, terminal deoxynucleotidyl transferase (TdT), and cell surface markers in childhood acute leukemia.

The purpose of this report is to compare measurements of enzymatic activities and cell surface markers as methods of distinguishing subtypes of lymphoid leukemias of childhood. Twenty-six children ages 2-15 yr were studied. Terminal deoxynucleotidyl transferase (TdT) activity was high in blasts from all 20 children with either null or T cell acute lymphoblastic leukemia. The activity of adenosine deaminase per cell was higher (P less than 0.005) and that of TdT lower (p less than 0.05) in T than in null cell lymphoblasts, although there was some overlap in values. Blasts from 3 children with acute lymphoid leukemia were positive for surface-associated immunoglobulins. The neoplastic lymphoid cells from these children differed from T and null cell leukemic lymphoblasts by having very low levels of TdT and adenosine deaminase activity. Measurements of adenosine deaminase and TdT may complement measurements of cell surface markers and distinguish biochemical subtypes of acute lymphoid leukemia.