Search

A man in his fifties presented with a lump in his left anal/perineal region, which was clinically thought to be a lipoma and was excised. No preoperative imaging was available. Review the high-quality, interactive digital Aperio slide at http://virtualacp.com/JCPCases/jclinpath-2019-206337/ and consider your diagnosis. 1. Epithelioid angiosarcoma (EAS). 2. Epithelioid malignant peripheral nerve sheath tumour (eMPNST). 3. Malignant rhabdoid tumour (MRT). 4. Melanoma. 5. Proximal epithelioid sarcoma (ES). 6. Pseudomyogenic haemangioendothelioma (PH). The correct answer is after the Discussion. The diagnosis in this case is proximal ES. This was based on the following morphological features and immunohistochemistry. The sections show a cellular tumour composed of large polygonal cells with vesicular nuclei with prominent nucleoli and abundant eosinophilic granular cytoplasm (figure 1A). There are 8 mitoses per 10 high-power fields and focal necrosis. The tumour grows in sheets to form large nodules with a mild intratumoural lymphoid population and infiltrates into the surrounding fibroadipose tissue. The morphology and the immunohistochemistry findings are in keeping with proximal-variant epithelioid sarcoma (PES). The tumour shows strong and diffuse expression of epithelial membrane antigen (EMA) and CD34, with patchy expression of AE1/AE3 (figure 1B,C). There is also loss of nuclear expression of INI1 (figure 1D). There is no expression of MNF116, CAM5.2, S100 protein, CD30, CD31, FLI1, ERG, SOX10, HMB45, MelanA, desmin, smooth muscle actin (SMA), myogenin, CD45, PLAP or prostate-specific antigen. Figure 1 Scanned virtual slide (proximal-type ES). Proximal-type ES. (A) The tumour is composed of sheets and nests of relatively large and monomorphic epithelioid cells with vesicular nuclei and prominent nucleoli. (B,C) There is diffuse and strong expression of CD34 (B) and epithelial …

A man in his 30s presented with back pain and was found to have a tumour in the posterior chest wall. Imaging showed an expansile mass measuring up to 6.7 cm, centred on the left posterior 11th rib with diffuse cortical destruction. The tumour displaced the left hemidiaphragm, and was in contact with the spleen, with no infiltration seen. There was no involvement of the overlying skin. PET-CT showed the lesion to be inhomogeneously hypermetabolic, with a mainly peripheral distribution of FDG. Staging imaging showed no other abnormality. The patient was otherwise well with no medical history and no significant family history. A CT-guided biopsy was performed. Review the high-quality, interactive digital Aperio slide at http://virtualacp.com/JCPCases/jclinpath-2019-206338/ and consider your diagnosis. 1. Metastatic carcinoma. 2. Alveolar rhabdomyosarcoma (ARMS). 3. Sclerosing epithelioid fibrosarcoma (SEF). 4. Spindle cell/sclerosing rhabdomyosarcoma. 5. Osteosarcoma. 6. Ossifying fibromyxoid tumour (OFMT). This is a tumour composed of relatively uniform, minimally to mildly pleomorphic, medium-sized cells with round to ovoid nuclei and clear to lightly eosinophilic cytoplasm. The cells are present in groups, nests and occasionally individually, within densely fibrous stroma, with areas suspicious of osteoid formation. In this case the tumour is diffusely and strongly positive for MUC4 and CD99, and focally for CD57. This particular case is negative for AE1/AE3, Cam5.2, CK7, TTF1, desmin, smooth muscle actin (SMA), myogenin, FLI1, neuron-specific enolase, CD56, synaptophysin, chromogranin, glial fibrillary acidic protein, TLE1, CD45 and CD138. There is a normal staining pattern for p53, and INI expression is retained in nuclei. …