In the given differential diagnosis, p63 appears relatively specific to SCSCC and adds a useful nuclear marker to the available repertoire. The findings also suggest that cytokeratins MNF116 and CK34betaE12 may be more useful than standard cytokeratins in labeling SCSCC.

Uniform management of flat DIN 1 (flat epithelial atypia) on core needle biopsy (CNB) concerning surgical excision or clinical follow-up are lacking. In a retrospective review of 1,751 CNB over an 8-year period, we found 63 cases with flat DIN 1 as the most advanced lesion; follow-up was available in 55 cases. Of the 63 patients, 24 had a subsequent biopsy for 15 days to 10 years after the initial CNB, an infiltrating carcinoma was found in nine (14.3%) patients, seven (11.1%) in the ipsilateral, and two (3.2%) in the contralateral breast. Five underwent an excisional biopsy of the ipsilateral breast within less than 3 months of the initial CNB; none had either an invasive or intraepithelial carcinoma. Based on our findings, we consider flat DIN 1 a marker of slightly increased risk for subsequent development of invasive breast carcinoma. When flat DIN 1 is found on CNB as the most advanced lesion after mammographic correlation, an excisional biopsy is not mandatory; however, close follow-up is advised with repeat mammograms for early detection of any clinically occult carcinoma in the vicinity of flat DIN 1 that may have been missed by the CNB.

Squamous cell carcinoma of the pancreas is a rare condition. The incidence has been estimated at approximately 1% of all pancreatic malignancies. The histogenesis is uncertain, but it has been proposed to originate from areas of squamous metaplasia of pancreatic ductal epithelium. We present a case of a 56-year-old man who presented with back pain and was found to have a squamous cell carcinoma of the pancreas without evidence of metastatic disease. Three months after en bloc resection with negative margins and lymph nodes, he presented with widely metastatic disease. A review of the literature on the topic is presented, and the poor prognosis of this rare tumor, despite complete surgical resection, is discussed.

We failed to find amplification or rearrangement of the PTH gene but documented hypomethylation of the PTH promoter in tumor tissue. We found that PEPP1 cells support expression of a reporter gene containing regulatory sequences from the human PTH gene promoter. Therefore, this is the first report documenting ectopic PTH production by a tumor as the result of transactivation of the PTH gene. PEPP1 cells may be useful for future studies aimed at elucidating the details of PTH gene regulation.

The p63 gene, a member of the p53 family, is an epithelial marker expressed in embryonic ectoderm, breast myoepithelium, prostate, oral epithelium, epidermis, and urothelium. The DeltaN-p63 isoforms of p63, which are believed to behave as oncogenes, are expressed in squamous cell carcinoma, basal cell carcinoma, and transitional cell carcinoma. Only a few authors have looked for p63 expression in thymomas and normal thymus. We, therefore, thought of undergoing such a search by taking advantage of our archival material. We studied 66 cases of thymoma (1 type A, 8 type AB, 12 type B1, 19 type B2, 12 type B3, and 14 type C/thymic carcinoma) and 10 specimens of normal human thymus arranged in tissue microarrays. All thymomas (including thymic carcinomas) were positive for p63 regardless of type. Most of the epithelial cells of the normal thymus were also positive for this marker.

Only a few synovial sarcomas arising in the gastrointestinal tract have been reported, most of them are from the esophagus. We report clinical, histopathologic, and immunohistochemical features of 10 gastric synovial sarcomas. These tumors occurred in 4 males and 6 females with mean and median age of 52 years (range, 29 to 68 y). None of the patients had evidence of synovial sarcoma elsewhere. The tumor sizes ranged from 0.8 to 15 cm (mean, 3 cm). Two tumors were large transmural masses of 8 and 15 cm, and 8 were 0.8 to 6 cm, ulcerated cuplike or plaquelike or oval lesions predominantly involving the luminal side. Histologically, 9 tumors were monophasic one also having a poorly differentiated round cell component, and one was biphasic. Microscopic calcifications were present in 2 tumors. At least focal keratin (AE1/AE3 cocktail, keratin 7) and/or epithelial membrane antigen-positivity were detected in all tumors, and there was no CD34 or KIT-immunoreactivity. SYT-SSX fusion transcripts were demonstrated in 7 cases studied by a polymerase chain reaction-based fusion transcript assay. Five patients had a partial gastrectomy, and 5 underwent wedge or segmental resections. Two patients had received chemotherapy after surgery, but none had postoperative radiation. Four patients with plaquelike or cuplike tumors < or =3 cm were alive and well 1, 2, 2, and 18.5 years after surgery. Two patients died of tumor 25 and 29 months after surgery. One of them had a large 8-cm tumor, and another had a 2-cm tumor with a poorly differentiated component. Two patients were alive with recurrences 6 and 48 months after diagnosis. Synovial sarcoma rarely occurs as a gastric primary tumor. It has a variable prognosis depending on tumor size and differentiation, and should be considered in the differential diagnosis of KIT-negative gastric spindle cell neoplasms.

Reduction mammoplasty is a frequently performed procedure for the treatment of macromastia and for the achievement of symmetry in breast cancer patients following lumpectomy. Slides from 516 consecutive bilateral reduction mammoplasties performed for macromastia over 15 years were reviewed. Among these, 92 (18%) low-risk ductal intraepithelial neoplasia/intraductal hyperplasia, 28 (5%) ductal intraepithelial neoplasia 1 (1 low-grade ductal carcinoma in situ, 11 atypical intraductal hyperplasia, and 16 flat type), 17 (3%) lobular intraepithelial neoplasia, and 1 (0.2%) tubular carcinoma were identified. The patients were categorized into 3 age groups: <40 (n=352), 40 to 50 (n=107), and over 50 years (n=57); the frequency of the lesions increased with age. These data confirm the low frequency of clinically occult malignancies identified in reduction mammoplasty specimens and provide substantial information about the frequency of a variety of intraepithelial proliferations. Preoperative mammography, specimen orientation, and inking of margins with 1 color are advised when reduction mammoplasty is scheduled for women>or=40 years of age.

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