Clear Cell Rhabdomyosarcoma

Abstract

A clear cell rhabdomyosarcoma was studied by light microscopy, histochemistry, immunohistochemistry, and electron microscopy. It was a large, painful left parapharyngeal mass in a 10-year-old boy with intracranial extension and cervical metastatic enlarged lymph nodes. Tumor tissue was macroscopically grayish. At microscopic examination, the architecture was diffuse and focally alveolar. Tumor cells were of three types. Most cells were large, round or polygonal, with abundant clear vacuolated cytoplasm. Fibrils were sometimes found to be present around the nucleus. Nuclei often had irregular outlines and multiple nucleoli. Mitotic activity was high. Some round or elongated cells had eosinophilic fibrillar cytoplasm and were found to have a few double striations. A few cells were round and medium sized with a high nucleocytoplasmic ratio. Periodic acid-Schiff stain demonstrated huge amounts of intracytoplasmic glycogen in clear cells. Tumor cells showed positive immunostaining for muscle markers (desmin, muscle actins, dystrophin). Electron microscopy showed large lakes of glycogen, lipid droplets, and striated muscle features.

Upstream CpG island methylation of the PAX3 gene in human rhabdomyosarcomas

“…These levels were still higher than those of the nine hypomethylated ARMS, which had a mean methylation percentage of 6.5%. Again, we cannot exclude the possibility that cryptic alveolar elements in mixed alveolar/embryonal tumors contributed to the relatively low methylation levels of these three ERMS 70,71. In a recent study on a tumor with mixed ERMS and ARMS histology, genetic features of both embryonal and alveolar foci more closely resembled ARMS, despite the presence of ERMS histology 72.…”

Rhabdomyosarcoma with Pseudolipoblasts Arising in Ovarian Carcinosarcoma: A Distinctive Postchemotherapy Morphologic Variant Mimicking Pleomorphic Liposarcoma

“…Their cytoplasm is rich in glycogen, demonstrable by PAS stain. Electron microscopy shows large lakes of glycogen and features of striated muscle, with paranuclear thick and thin filaments [5] as well as lipid droplets [6]. While the number of reported cases is too small for conclusions about behaviour, clear cell variant rhabdomyosarcoma has been shown to present with massive bone marrow involvement in the absence of a primary site of disease [7].…”

Parapharyngeale Raumforderungen Differenzialdiagnostik anhand von Fallbeispielen

“…Neurogene Tumoren treten in bis zu 25% der Fälle auf, die zwar häufig zur Verlagerung oder sogar Ausdünnung des Nerven führen, sich aber selten in einer präoperativ sichtbaren Nervenläsion manifestieren [16,19]. Raritäten stellen extrakranielle Meningeome [15,27], Sarkome [4,21], Leiomyome [1] oder Neuroblastome [17,26] dar. Die restlichen Tumoren setzen sich aus einer sehr heterogenen Gruppe zusammen, wie z.…”