Aspiration biopsy of osseous metastasis of retroperitoneal paraganglioma. Report of a case with cytologic features and differential diagnostic considerations.

BACKGROUND: Paragangliomas are uncommon tumors, only 10% of which are malignant, as evidenced by metastatic disease. It is rare for paraganglioma to present with symptomatic osseous metastases. CASE: A retroperitoneal paraganglioma presented in a 52-year-old man as painful metastases in the rib and vertebrae. Fine needle aspiration (FNA) of a lumbar vertebral lesion showed cells arranged singly and in loose clusters with fragile, vacuolated or finely granular cytoplasm, marked anisonucleosis and mitoses. Rare zellballen-type structures and intranuclear inclusions were present. Immunohistochemical studies of a subsequent FNA core biopsy of the retroperitoneal mass showed strong immunoreactivity with chromogranin and negative staining for keratin; that was helpful in differentiating this tumor from others in the differential diagnosis. CONCLUSION: The cytologic diagnosis of paraganglioma is difficult as these tumors exhibit a plethora of features that overlap those of many other neoplasms. The diagnosis can be confirmed with appropriate immunohistochemical studies of corresponding core biopsies.

Cryptococcal osteomyelitis. Report of a case with aspiration biopsy of a humeral lesion with radiologic features of malignancy.

BACKGROUND: Osteomyelitis due to Cryptococcus neoformans typically exhibits lytic lesions on radiographs. Extensive periosteal reaction is an uncommon feature. CASE: A 68-year-old man presented with pain and swelling in the left elbow. Radiologic studies exhibited a lytic humeral lesion with extensive periosteal reaction, interpreted as a malignant neoplasm. Fine needle aspiration biopsy (FNA) revealed abundant cryptococcal organisms. CONCLUSION: Cryptococcus is an uncommon cause of lytic osseous lesions that may mimic malignant neoplasms. Extensive periosteal reaction may support a radiologic diagnosis of primary osseous malignancy in rare cases. FNA with examination of Diff-Quik-stained slides may be employed for distinguishing cryptococcal osteomyelitis from malignant tumors and for prompt identification of the organisms.