No abstract available.
Granular Cell Tumor*

Synovial sarcoma arises in the para-articular tissues, and it can also occur in various unexpected sites. We report a rare case of primary monophasic synovial sarcoma (MSS) arising in the mesentery. A 59-year-old man presented with a palpable abdominal mass. On microscopic examination, the entire tumor comprised a dense proliferation of the spindle cells without epithelial components. The tumor cells were positive for transducin-like enhancer of split 1, bcl-2, epithelial membrane antigen and CD99 but negative for CD34, CD117, alpha-smooth muscle actin, cytokeratin, and calretinin on immunohistochemistry. The reverse transcriptase-polymerase chain reaction revealed a single 151-bp fragment representing the SYT-SSX2 fusion transcript. Because mesenteric MSS is extremely rare and many cases display histologic findings that overlap with those of more frequently involved tumors such as hemangiopericytoma and gastrointestinal stromal tumor, there is a chance of making an incorrect diagnosis that can result in an inappropriate treatment.
Actins ; Calcium-Binding Protein, Vitamin D-Dependent ; Gastrointestinal Stromal Tumors ; Hemangiopericytoma ; Humans ; Immunohistochemistry ; Keratins ; Mesentery ; Middle Aged ; Mucin-1 ; Muscles ; Oncogene Proteins, Fusion ; Reverse Transcriptase Polymerase Chain Reaction ; Sarcoma ; Sarcoma, Synovial

BACKGROUND: There has been an increase in the use of fine needle aspiration cytology (FNAC) for the diagnosis of parathyroid lesions (PLs). Differentiation between a thyroid lesion and a PL is not easy because of their similar features. We reviewed parathyroid aspirates in our institution and aimed to uncover trends in diagnostic criteria. METHODS: We selected 25 parathyroid aspirates (from 6 men and 19 women) confirmed surgically or immunohistochemically from 2006 to 2011. RESULTS: Major architectural findings of PLs include scattered naked nuclei, loose clusters, a papillary pattern with a fibrovascular core, tight clusters, and a follicular pattern. These architectures were commonly admixed with one another. Cytological features included anisokaryosis, stippled chromatin, a well-defined cell border, and oxyphilic cytoplasm. Eighteen of the 25 patients were diagnosed with PL using FNAC. Seven patients had been misdiagnosed with atypical cells (n=2), benign follicular cells (n=2), adenomatous goiter (n=2) and metastatic carcinoma (n=1) in FNAC. Using clinicoradiologic data, the sensitivity of the cytological diagnosis was 86.7%. The cytological sensitivity decreased to 50% without this information. CONCLUSIONS: FNAC of PL is easily confused with thyroid lesions. A combination of cytological parameters and clinical data will be required to improve the diagnostic sensitivity of PLs.
Biopsy, Fine-Needle* ; Chromatin ; Cytoplasm ; Goiter ; Humans ; Male ; Thyroid Gland