Pediatric Blood & Cancer | 2019
Partial response to carboplatin, etoposide phosphate, and atezolizumab in a pediatric patient with high‐grade metastatic tumor with rhabdoid and focal neuroendocrine features
Abstract
To the Editor: Metastatic solid tumors remain challenging to cure.1–3 Rarely, nondiagnostic pathology further complicates treatment and prognosis.4 We present the case of a child with an undifferentiated, metastatic malignancy showing rhabdoid and neuroendocrine features exhibiting a partial response to carboplatin, etoposide phosphate, and atezolizumab. A 7-year-oldmale presentedwith a large retroperitoneal mass with liver metastases and gastric outlet obstruction. Pathology revealed rhabdoid histology with uniform cells, focal nuclear pleomorphism, and large central nucleoli, although expression of INI-1 and BRG1 was retained, making a diagnosis of malignant rhabdoid tumor unlikely.5 The tumor expressed epithelial and mesenchymal markers including diffuse positivity for cytokeratin Cam 5.2, and focal staining for cytokeratin AE1/AE3, pancytokeratin, and vimentin. Patchy positive staining for synaptophysin and chromogranin implied features of neuroendocrine differentiation.6 Beta-catenin staining was