A 152-week-old male Royal College of Surgeons (RCS) rat kept as a non-treated animal in a long-term animal study presented with a soft mass in the anterior mediastinum, which adhered to the pleura of the lung. Histopathologically, the mass mainly consisted of round to short spindle-shaped tumor cells that had infiltrated through the hyperplastic thymic tissue. The tumor cells were arranged in l...

Solitary fibrous tumor (SFT) is a rare spindle-cell neoplasm, especially in the thyroid. We report a case of primary solitary fibrous tumor of the thyroid gland in a 37 year-old Chinese man. The tumor was characterized by bland-looking spindle cells admixed with thin and thick collagen fibers. On immunohistochemistry study indicated that tumor cells were diffusely positive for CD34, Bcl-2 and C...

The heterodimeric tumor-suppressor complex BRCA1/BARD1 exhibits E3 ubiquitin ligase activity and participates in cell proliferation and chromosome stability control by incompletely defined mechanisms. Here we show that, in both mammalian cells and Xenopus egg extracts, BRCA1/BARD1 is required for mitotic spindle-pole assembly and for accumulation of TPX2, a major spindle organizer and Ran targe...

  Background and Objective: Inflammatory pseudotumor  is a lesion composed of proliferating spindle cells with mixed inflammatory infiltrates. Some authors have proposed the name inflammatory myofibroblastic tumor as a proper descriptive term rather than the vague inflammatory pseudotumor. The aim of this study was to verify the myofibroblastic origin of spindle cells in idiopathic orbital inf...

The light microscopic and immunohistochemical characteristics of a case of fibrous histiocytoma of intermediate malignancy arising from the parotid gland are presented. This neoplasm is rare in this site and must be distinguished from other spindle cell tumors of the parotid gland, particularly those of epithelial and myoepithelial origins. Histologic characteristics similar to those displayed ...

Cell division orientation during animal development can serve to correctly organize and shape tissues, create cellular diversity or both. The underlying cellular mechanism is regulated spindle orientation. Depending on the developmental context, extrinsic signals or intrinsic cues control the correct orientation of the mitotic spindle. Cell geometry has been known to be another determinant of s...

We report a case of double uterine tumor resembling ovarian sex cord tumor (UTROSCT). The tumor was composed of sex cord-like cords, nests and tubules, and bundles of myoid cells. The lesion was interesting especially in regard to histogenesis of intratumoral myoid cells. It is not known whether these cells are neoplastic or whether they represent preexisting myometrial smooth muscle cells entr...

Sarcomatoid carcinoma is a rare biphasic tumor characterized by a combination of malignant epithelial and mesenchymal cells. We report a rare case of sarcomatoid carcinoma of the colon. A 41-yr-old woman was hospitalized with a history of melena. Total colectomy was performed under the impression of colonic carcinoma. Histologically, the tumor was composed of differentiated adenocarcinoma in su...

CONTEXT Anaplastic carcinoma of the pancreas is a rare undifferentiated variant of ductal adenocarcinoma, which commonly displays sarcomatoid spindle-cell and pleomorphic growth patterns. Anaplastic carcinoma of the pancreas associated with mucinous cystic neoplasm has rarely been reported. CASE REPORT Here we report a unique case of an anaplastic carcinoma of the pancreas in association with...

Sarcomatoid change has been well documented in the various subtypes of renal cell carcinoma (RCC) and its presence is known to portend a worse prognosis in RCC. Mucinous tubular and spindle cell carcinoma is a RCC subtype, which is defined as polymorphous histology wherein the spindled epithelial cell is an inherent carcinomatous component. Many of these putatively low-grade tumors have been pr...