No abstract

Primitive neuroepithelial differentiation in malignant peripheral nerve sheath tumors (MPNSTs) has been reported in children but is extremely rare in adults. The authors report the case of a 70-year-old woman who presented with swelling of the right leg of 1-month duration. Fine-needle aspiration cytology was suggestive of a benign peripheral nerve sheath tumor. Histopathological examination of the excised mass revealed a MPNST with spindle-cell areas and a few round-cell areas with rosettes. The spindle cells showed positive immunoreactivity for S-100 protein and vimentin and negativity for desmin, confirming their nerve sheath origin. The round cells were immunoreactive for synaptophysin and chromogranin, indicating primitive neuroepithelial differentiation. These cells did not stain for CD99, which is consistently expressed by the cells of primitive neuroectodermal tumors (PNETs) of bone and soft tissue but not by central nervous system (CNS) PNETs or medulloblastomas. In this case, the PNET-like focus resembled a CNS-PNET.

Schwannomatosis is a term used to describe patients with multiple nonvestibular schwannomas with no other stigmata of neurofibromatosis type-2 (NF2). Neuroblastoma-like schwannoma is a rare subtype of schwannoma, with histological features resembling a neuroblastoma. This case is probabaly the second case of very uncommon neuroblastoma-like schwannoma, in a patient of schwannomatosis.

Mesoblastic nephroma (MN) is the most common renal tumor diagnosed in infancy. A case of congenital MN was diagnosed in a 6-month old child by fine-needle aspiration cytology. The smears were cellular and consisted of plump spindle cells arranged in clusters along with scattered naked nuclei in the background. Blastemal, epithelial, or glomeruloid structures were not seen. Considering the age and the cytomorphology, a diagnosis of cellular variant of MN was offered which was confirmed on histopathology. Unlike Wilms tumor, preoperative chemotherapy is not required for MN. Hence cytologic diagnosis is important.

Extralobar sequestration of lung is a rare congenital malformation frequently diagnosed during repair of congenital diaphragmatic hernia. However, the combined association of congenital diaphragmatic hernia with both pulmonary sequestration and malrotation of gut is rare. We report a case of a 1-year-old girl with extralobar sequestration of lung and malrotation of gut detected during the repair of diaphragmatic hernia. The histopathological examination of the sequestered lobe revealed dilated bronchioles, alveolar ducts and alveoli along with dilated subpleural and peribronchiolar lymphatics and areas of type II congenital pulmonary airway malformation.