Bone & Soft Tissue Pathology
Epithelioid Sarcoma - A Clinicopathologic and Immunohistochemical Analysis
Reassessment of the Usefulness of Frozen Section Analysis for Hip and Knee Joint Revisions
Epithelioid Sarcoma
Epithelioid sarcoma (ES) is rare with a poor prognosis and for which a loss of INI1 expression has been recently reported. We report a study of 106 cases with clinical, histologic, and immunohistochemical data, including INI1 expression, and follow-up data. Of the 106 cases, 70 were the conventional subtype and 36 the large cell subtype. INI1 was negative in 86 cases (81.1%): 57 (81%) of 70 conventional and 29 (81%) of 36 large cell subtypes. Treatment modalities were available for 76 and follow-up for 80 patients. Of the 80 patients, 43 (54%) experienced metastasis and 25 (31%) died of the disease. Univariate analysis indicated that tumor size and mitotic index were significant for metastasis-free survival, whereas proximal location, tumor size, tumor multifocality, and mitotic index were significant for overall survival. Loss of expression of INI1 is frequent in the conventional and large cell subtypes of ES and can be used as a diagnostic marker, but it has no prognostic impact.
Reassessment of the Usefulness of Frozen Section Analysis for Hip and Knee Joint Revisions
Intraoperative frozen section (FS) consultation is used in evaluating possible infection in cases of hip and knee revision arthroplasty, serving as an adjunct to preoperative and intraoperative studies. We examined our experience for more than 11 years to determine if FS examination had value when sections were sent unselectively. We reviewed 244 cases, 132 with available culture results. The criterion for the presence of acute inflammation was more than 5 polymorphonuclear leukocytes per high-power field (hpf) in at least 5 separate hpfs, excluding surface inflammatory exudate and fibrin. Only 27 cases (11.1%) demonstrated positive FS or paraffin section results. In comparison with intraoperative culture, the sensitivity, specificity, positive predictive value, and negative predictive value for FS analysis alone (on review) were 29%, 95%, 40%, and 92%. As currently used, FS analysis has excellent specificity and negative predictive value but poor sensitivity and positive predictive value. We suggest that FS examination be used more selectively in conjunction with other studies, namely erythrocyte sedimentation rate and C-reactive protein.