Well-Differentiated/Dedifferentiated Liposarcoma Arising in the Upper Aerodigestive Tract: 8 Cases Mimicking Non-adipocytic Lesions

Well-differentiated (WDL) and dedifferentiated liposarcomas (DL) of the pharynx, larynx and oral cavity are rare, often mimicking benign lipomatous neoplasms or non-lipogenic mesenchymal tumors. Cases of WDL/DL arising in the upper aerodigestive tract, exclusive of the cervical esophagus, were reviewed. Morphologic features, ancillary studies, including fluorescence in situ hybridization (FISH) studies for CPM/MDM2, and clinical data was catalogued. Eight WDL/DL (4 WDL, 4 DL); were identified in patients ranging from 32 to 77 years (median 52.5 years; 6 males, 2 females) with sites of origin including hypopharynx (5 cases), larynx (2 cases) and oral cavity (1 case). Six of the 8 cases were received for expert consultation, and the remaining 2 cases were initially misdiagnosed as benign lymphangiomatous or fibroepithelial polyps. Morphologically, 4 tumors had areas mimicking various non-lipomatous soft tissue tumors including nodular fasciitis, mammary-type myofibroblastoma, low-grade myofibroblastic sarcoma and undifferentiated pleomorphic sarcoma, 2 cases simulated benign hypopharyngeal polyps, and 1 lesion was notable for a dense lymphoplasmacytic infiltrate suggestive of hematolymphoid neoplasm or IgG4-related sclerosing disease. FISH showed amplification of CPM/MDM2 (8/8 cases). All cases (4/4) with longer than 1-year of follow-up recurred (45-118 months) with 1 tumor showing progression to DL. WDL/DL presenting in the upper aerodigestive tract are rare and diagnostically challenging. Awareness of the morphologic spectrum of WDL/DL coupled with appropriate use of MDM2 FISH is essential for accurate classification and management, as these tumors appear to have a high risk for local recurrence and eventual dedifferentiation in these anatomical locations.

Mesenchymal chondrosarcomas showing immunohistochemical evidence of rhabdomyoblastic differentiation: a potential diagnostic pitfall

The diagnosis of mesenchymal chondrosarcoma, a distinctive biphasic malignant neoplasm harboring the HEY1-NCOA2 gene fusion and consisting of primitive round to spindled cells admixed with foci of relatively mature hyaline cartilage, is usually straightforward by morphologic evaluation alone. However, in the setting of a limited biopsy, specimens lacking cartilage generate a broad differential diagnosis, encompassing a variety of other primitive sarcomas, including spindle cell/sclerosing rhabdomyosarcoma. Although a small number of cases of mesenchymal chondrosarcoma with aberrant skeletal muscle marker expression have been reported, pathologists are largely unaware of this potential diagnostic pitfall. We report 6 additional cases of mesenchymal chondrosarcoma showing expression of multiple skeletal muscle markers, including one case initially misdiagnosed as "spindle cell/sclerosing rhabdomyosarcoma" on needle biopsy. Awareness of this phenomenon and judicious application of molecular diagnostic testing for the HEY1-NCOA2 fusion are critical to avoid misclassification of mesenchymal chondrosarcoma as rhabdomyosarcoma, with potentially adverse patient impact.

Veno-occlusive disease of the liver after blood and marrow transplantation: analysis of pre- and post-transplant risk factors associated with severity and results of therapy with tissue plasminogen activator

We reviewed our blood and marrow transplantation (BMT) database from April 1982 to July 1996 and identified 111 of 474 patients with serum bilirubin concentration (SBR) > or = 34 micromol/l for two consecutive days within the first 20 days after related allogeneic or autologous BMT. Of the 111, 73 fulfilled the Seattle criteria for veno-occlusive disease of the liver (VOD) and had no other obvious cause for liver dysfunction. The patients were 16-60 years old (median, 39 years), and 41 were male (56%). Fourteen patients (19%) had autologous BMT, and 59 (81%) had allogeneic BMT. Twenty-eight (38%), 12 (16%), and 33 (45%) patients had severe, moderate, and mild VOD, respectively, by Seattle criteria. None of 23 patients with maximum (max) SBR > or = 257 micromol/l survived, all patients with max SBR < or = 128 micromol/l survived, and 7 of 15 patients (47%) with max SBR 128-257 micromol/l survived. The only pre-transplantation risk factor predictive of severe VOD was advanced disease state (P = 0.035), and the only transplant factors that predicted severe VOD were max SBR (P = 0.01) and maximum blood urea level (P = 0.03). Ten patients (all with creatinine levels > or = 150 micromol/l) were treated with tissue plasminogen activator; only two had a significant response and only one survived beyond day 120.