Effect of chemotherapy on initial compressive osseointegration of tumor endoprostheses.

Chemotherapy has long been suspected of having an adverse effect on bone healing. Massive tumor endoprostheses which achieve osseointegration via compressive force provide a unique model to study the effects of chemotherapy on bone healing. We compared distal femoral bone hypertrophy in patients who received chemotherapy with those who did not. Fifty four patients underwent distal femoral reconstruction with a compression implant. Thirty patients received chemotherapy (Group 1), and 24 did not (Group 2). The group of patients receiving chemotherapy was younger, had lower body mass indices, and had different diagnoses compared to the group of patients not receiving chemotherapy. We used a standardized technique to measure bone growth at the bone-prosthetic interface. The rate of cortical width increase at the bone-prosthetic junction was faster in Group 2 compared to Group 1. Similarly, the increase in cortical width from immediate postop to 3 months and 6 months postop was greater in Group 2 when compared to Group 1. The data suggest chemotherapy administration for musculoskeletal malignancy has a substantial initial adverse effect on bone hypertrophy and a trend towards reduced prosthetic survival. These findings have important implications for the patients with musculoskeletal tumors.

Spindle cell sarcoma of the kidney with ganglionic elements (malignant ectomesenchymoma) associated with chromosomal abnormalities and a review of the literature.

PURPOSE: Malignant ectomesenchymomas are tumors that exhibit both mesenchymal and neuroectodermal elements (1). We report a case thought to represent a malignant ectomesenchymoma arising in the kidney with cytogenetic abnormalities that may provide insight into the biologic basis for this unusual tumor. METHODS: We discuss the clinical features, histopathologic findings, cytogenetics, treatment, and outcome of a child with a malignant ectomesenchymoma arising in the kidney. RESULTS: An asymptomatic 16-month-old boy had a large abdominal mass. The resected tumor contained sheets of spindled cells that expressed mesenchymal markers and cartilaginous differentiation, interspersed with clusters of ganglion cells that expressed neural markers. No blastemal or epithelial elements were demonstrated. Cytogenetic analysis of the tumor revealed a hyperdiploid count with multiple numerical and structural abnormalities, including a translocation between chromosomes 12 and 15. In addition to the surgical resection, the patient was successfully treated with adjuvant chemotherapy and local radiation therapy. CONCLUSION: This is the first report of which we are aware of an ectomesenchymoma arising within the kidney. A subset of malignant ectomesenchymomas may be related to the Ewing's family of tumors (EFTs) (2), but this case did not exhibit cytogenetic features consistent with EFT. Thus, the malignant ectomesenchymoma phenotype probably represents a heterogeneous group of tumors with different genotypes and origins. Cytogenetic analysis may be instrumental in determining the appropriate therapeutic approach when faced with such a neoplasm. The outcomes of 12 other children with ectomesenchymoma are reviewed.

Lymphoblast morphology in predicting leukemic meningeal relapse with low chamber count and lymphoblasts.

The diagnostic criteria for meningeal relapse (MR) of acute lymphoblastic leukemia (ALL) are a cerebrospinal fluid (CSF) chamber count of more than five leukocytes per microliter and a cytomorphological evaluation revealing lymphoblasts. A dilemma arises when confronted with a patient with a low CSF white blood cell (WBC) chamber count and lymphoblasts. We utilized a scoring system to review lymphoblast morphology in 12 such patients. A cell was defined as a lymphoblast if it could not be easily categorized as a lymphocyte, monocyte. histiocyte, or granulocyte. Each lymphoblast was scored on four parameters: presence of nucleoli, homogeneous distribution of chromatin, nucleocytoplasmic ratio greater than 75%, and nuclear irregularity. Cells were scored without knowledge of the patients' out come. Seven patients eventually developed MR by current criteria and five patients never relapsed. The mean lymphoblast scores for patients that did and did not relapse were 2.35 and 1.53, respectively (P < .001). The percent of cells scored as lymphoblasts was also significantly higher in patients that relapsed, 36.9% vs. 19.4% (P = .01). Our study shows that careful cytomorphologic analysis can predict which patients with low chamber counts and "blasts" on cytocentrifuge examination will progress to meningeal relapse. We recommend reviewing the definition of MR and using a scoring system when confronted with blasts in a low chamber count cerebrospinal fluid specimen.

Pediatric pulmonary artery thromboembolism: an illustrative case.

Correct and early diagnosis, along with appropriate therapy, should limit mortality. In the pediatric population, signs and symptoms may be subtle. PE should be on the differential diagnosis in patients that present with dyspnea in association with significant risk factors, chest pain, or hemoptysis. PE may be missed if a high index of suspicion is not maintained. In a patient with a PE, an appropriate hypercoagulable workup (Table 1) needs to be considered prior to initiation of anticoagulation therapy. This case highlights the need for further awareness.