Adenosine triphosphatase activity of crystalline inclusions in alveolar soft part sarcoma. An ultrahistochemical study of a case.

A case of alveolar soft part sarcoma was studied by light and electron microscopy and by electron microscopic enzyme histochemistry of adenosine triphosphatase (ATPase) and 5'nucleotidase(5'Nase). The tumor showed distinct alveolar pattern and diastase resistant PAS positive crystalline inclusions were found in the cytoplasm. Ultrastructurally, characteristic rhomboid crystals and dense granules were observed and they were positive for Mg++- and Ca++-ATPases but negative for 5'Nase. Tumor cell membrane also showed positive activity of ATPase in addition to 5'Nase. These results would support the myogenous derivation of alveolar soft part sarcoma.