Pseudofungi in pericolic lymph nodes.
We report a case of extensive pseudofungi in the pericolic lymph nodes. A 45-year-old man presented with lower abdominal discomfort, and large solid and cystic masses were discovered in the pelvic cavity by computed tomography. Debulking of the masses (by means of a Hartmann operation) was performed under the clinical impression of a pelvic sarcoma, and histologically the masses demonstrated features of a malignant gastrointestinal stromal tumor. All pericolic lymph nodes demonstrated multiple septate hyphae-like structures with pigmentation, particularly in the subcapsular sinuses. These structures showed positive staining with periodic acid-Schiff, but Gomori methenamine silver staining was negative. The structures appeared to be composed of iron, phosphorus, and calcium by Perls iron and von Kossa stains and revealed deposition of electron-dense granules on electron microscopic examination. Energy-dispersive radiographic micro-analysis showed the structures to contain phosphorus, sulfur, potassium, calcium, and iron. Pseudofungi can be misinterpreted as true fungi with septate hyphae; therefore, a careful morphologic examination with appropriate special stains is mandatory.
Song
Dong Eun
DE
Department of Pathology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, South Korea.
Kahn
Andrea G
AG
Khang
Shin Kwang
SK
Ro
Jae Y
JY
D003937:Diagnosis, Differential; D046152:Gastrointestinal Stromal Tumors / Q000473:pathology / Q000601:surgery; D006801:Humans; D025301:Hyphae; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009181:Mycoses / Q000473:pathology*