Lipomatous tumors accompanied by spindle cell component are not frequently encountered, and there are still problems regarding their differential diagnosis, nature, and nomenclature. To contribute to ongoing efforts, we present the clinical, histologic, and immunohistochemical characteristics of 20 cases of spindle cell lipomatous tumors with atypical features that may also be called atypical spindle cell/pleomorphic lipomatous tumors. Of the patients, 13 were men and 7 were women with an average age of 57.5 years. The most commonly affected site was the extremities. Twelve tumors arose in the subcutaneous tissue, while eight cases were located in the deep soft tissues. Tumor margins were often ill-defined with invasion into the surrounding tissues. Microscopic examination revealed a wide spectrum of histologic features. All cases consisted of poorly marginated proliferation of mildly atypical spindle cells set in a fibrous or myxoid stroma with a variable amount of adipocytic component showing variation in adipocyte size and scattered nuclear atypia and frequent univacuolated or multivacuolated lipoblasts. Tumor cellularity and the relative proportion of the components were highly variable. One tumor showed morphologic features evocative of dedifferentiation and another one exhibited histological features resembling pleomorphic liposarcoma. None of the patients had recurrence or metastasis at follow-up.

Primary tumors of the paratesticular region are rare, with paratesticular sarcomas constituting a major proportion of these tumors, particularly in the elderly. The paratesticular region consists of mesothelial, various epithelial and mesenchymal cells and may therefore give rise to a number of tumors with various behaviors. Defining the association between the paratesticular mass and the testicle, and differentiation between benign and malignant masses using radiology is challenging, therefore the mass is usually considered to be malignant and radical orchiectomy with high ligation is performed. The present study reports the cases of seven patients with tumors of the paratesticular region and presents the clinical and significant histological features of the tumors. In total, two patients suffered from dedifferentiated liposarcoma (DDLS), two exhibited leiomyosarcoma, two exhibited low-grade fibromyxoid sarcoma and one case of undifferentiated pleomorphic sarcoma was identified. Radical orchiectomy with high ligation was performed in five cases; simple orchiectomy was performed in one case and excisional biopsy was performed in the remaining case. A leiomyosarcomatous and epithelial membrane antigen (EMA) positive whorl pattern was observed during microscopy in the two DDLS cases. Additionally, one of the low-grade fibromyxoid sarcoma patients exhibited pleomorphism and mitosis in focal areas. To the best of our knowledge, the present study is the second time low-grade fibromyxoid sarcoma cases with paratesticular localization have been reported in the literature. Of the seven cases, four patients succumbed to the disease, one patient is living with the disorder and the two cases of DDLS are living without the disease. Paratesticular sarcomas are often aggressive and a multidisciplinary approach is required for the diagnosis and treatment of these tumors.

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SummaryGiant cell tumor, excluding its prototype in bone, is usually a benign but local aggressive neoplasm originating from tendon sheath or soft tissue. Malignant behavior is uncommon. Visceral organ involvement including urinary bladder is rare. Giant cell tumors in visceral organs usually accompany epithelial tumors and the clinical behavior of giant cell tumor in urinary bladder is similar to its bone counterpart. Here, we report two cases of giant cell tumor located in urinary bladder in comparison with nine reported cases in the English literature. Concurrent noninvasive urothelial carcinoma was also described in all these previous reports and only one patient with follow-up died of disease. One of the two cases we present had no concurrent urothelial tumor at the time of diagnosis but had a history of a low grade noninvasive urothelial carcinoma with three recurrences. The histology of these two cases was similar to the giant cell tumor of bone and composed of oval to spindle mononuclear cells with evenly spaced osteoclast-like giant cells. Immunohistochemically, the giant cells showed staining with osteoclastic markers including CD68, TRAP, and LCA. Immunohistochemical expression of vimentin, CD68, LCA, and smooth muscle actin in mononuclear cells supported a mesenchymal origin with histiocytic lineage. The histologic and immunohistochemical properties in our cases as well as their clinical courses were consistent with a giant cell tumor. Consequently, tumors in urinary bladder showing features of giant cell tumor of bone may also be considered and termed "giant cell tumor".

Although infarction of parotid gland pleomorphic adenoma (PA) following fine-needle aspiration (FNA) has been well-documented, spontaneous infarction of PA has remained as an uncommon entity in the literature. To our knowledge, we report the second case of spontaneous infarction occurring in a parotid gland PA. A 44-yr-old man presented with a 2-yr history of slowly enlarging right parotid mass, which had become painful 1 mo before performing FNA biopsy. Smears revealed abundant necrotic debris, atypical squamous cells, and small cells with dark nuclei suggestive of a carcinoma. Histologic examination of the tissue fragments demonstrated degenerated clusters of cells and chondromyxoid matrix. The parotidectomy specimen had features consistent with those of an infarcted PA. Although appears to be rare, spontaneous infarction of PA should be considered in the differential diagnosis, since necrosis may mimic carcinoma and cause misinterpretation of necrosis as an indication of malignancy, in an otherwise benign salivary gland neoplasm.