Clinicopathologic analysis of renal and extrarenal angiomyolipomas: report of 44 cases.
BACKGROUND
Angiomyolipoma (AML) is a rare soft tissue tumor involving the kidneys, liver and other visceral organs. It is composed of smooth muscle cells, adipocytes and small- to medium-sized hyalinized vessels. The purpose of this study was to investigate the characteristic clinicopathologic manifestations of AML in different tissues.


METHODS
We collected 37 renal, four hepatic, one lymph node, one subcutaneous and one uterine cervical AML to analyze the clinical, histologic, histochemical and immunohistochemical variations of AML in different tissues.


RESULTS
Clinically, renal and hepatic AML were associated with tuberous sclerosis complex and predominate in women. There were several prominent pathologic differences between renal and extrarenal AML. First, none of the tumors were encapsulated except for the subcutaneous AML, which had a pseudocapsule. Secondly, the smooth muscle cells were usually epithelioid shaped in hepatic AML and occasionally in renal AML, but not in subcutaneous or uterine AML. Furthermore, hepatic AML characteristically showed extramedullary hematopoiesis and eosinophilic hyaline granules. Finally, only the tumor cells of renal, lymph node and hepatic AML had periodic acid-Schiff (PAS), PAS-D (after diastase digestion) positive granules and monoclonal mouse anti-human melanosome clone (HMB-45) immunoreactivity.


CONCLUSIONS
By combining the clinical, histologic, histochemical and immunohistochemical features, some discrepancies between the renal and extrarenal AML were observed, such as female predominance, association with tuberous sclerosis complex, morphology of the smooth muscle cells, presence of PAS, PAS-D positive granules and HMB-45 immunoreactivity in tumor cells. Extramedullary hematopoiesis and hyaline globules are unique to hepatic AMLs. These specific pathologic manifestations not only implicate the histogenesis of AML from different organs, but also assist in making a correct diagnosis.
Huang
P C
PC
Department of Pathology, Taichung Veterans General Hospital, Taiwan, ROC.
Chen
J T
JT
HO
W L
WL
D000328:Adult; D018207:Angiomyolipoma / Q000473:pathology*; D000818:Animals; D000951:Antigens, Neoplasm; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007680:Kidney Neoplasms / Q000473:pathology*; D008113:Liver Neoplasms / Q000473:pathology; D008297:Male; D058950:Melanoma-Specific Antigens; D051379:Mice; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000032:analysis; D012878:Skin Neoplasms / Q000473:pathology; D002583:Uterine Cervical Neoplasms / Q000473:pathology
D000951:Antigens, Neoplasm; D058950:Melanoma-Specific Antigens; D009363:Neoplasm Proteins