Peutz-Jeghers syndrome is caused by germline mutations in the LKB1/STK11 gene. Peutz-Jeghers syndrome is associated with an increased risk of developing intestinal and extraintestinal cancers, including pancreatic, lung, and breast carcinomas. LKB1 gene inactivation has recently been demonstrated in a subset of sporadic pancreatic and lung carcinomas. The role of the LKB1 gene in sporadic breast carcinomas remains unclear, though recent studies suggest inactivation only within papillary carcinomas. Using a commercially available polyclonal antibody that has been shown to mirror LKB1 genetic status in gastrointestinal and pulmonary carcinomas, the authors performed IHC on a large series of breast cancers using tissue microarrays (TMAs). All abnormal TMA results were confirmed using whole sections; specifically, whole sections from the donor blocks of lesions demonstrating diminished or absent LKB1 protein expression on TMA were evaluated to compare labeling of the lesion with that of the surrounding normal breast. In all cases, normal breast epithelium demonstrated strong cytoplasmic labeling (providing an internal positive control), whereas the stroma was nonreactive. Luminal cells typically labeled more strongly than myoepithelial cells. Among 70 invasive ductal carcinomas, 3 (4.3%) showed complete loss of LKB1 labeling, whereas 6 others (8.6%) showed diminished labeling. Of the eight intraductal carcinoma lesions adjacent to these invasive carcinomas, one (12.5%) showed complete loss of LKB1 labeling and one other (12.5%) showed diminished labeling; these results were identical to those of the adjacent invasive carcinomas. One of 10 (10%) hematogenous metastases of mammary carcinoma showed loss of LKB1 labeling. Nine of the 10 invasive carcinomas and both of the ductal carcinoma in situ (DCIS) cases showing loss of or diminished LKB1 expression were of high grade. In contrast, all 13 pure nonpapillary DCIS lesions, all 5 invasive lobular carcinomas and 3 accompanying lobular carcinoma in situ lesions, all 7 papillary DCIS lesions, and all 3 papillomas evaluated showed intact LKB1 labeling. Therefore, although frequent methylation of the LKB1 gene has been reported in papillary carcinomas of the breast, the authors did not find loss of protein expression in these lesions. Instead, it was found that loss of LKB1 protein expression occurs in a subset of high-grade in situ and invasive mammary carcinomas. The authors found LKB1 gene methylation in several of these invasive carcinomas. Given recent Western blot results indicating that diminished LKB1 expression in breast carcinomas correlates with shorter relapse-free survival, LKB1 IHC merits evaluation as a potential prognostic marker for breast carcinoma.

The authors report a previously undescribed small, well-demarcated breast tumor similar to a dermal cylindroma in a 63-year-old woman. The tumor was an incidental finding in a lumpectomy specimen for infiltrating lobular carcinoma. The cylindroma was surrounded by normal-appearing breast parenchyma and had the typical "jigsaw" pattern of epithelial basaloid islands. The islands showed focal squamous and myoepithelial differentiation. A notable number of reactive dendritic Langerhans cells permeated the epithelial cell islands, a feature considered to be characteristic of dermal cylindroma. There was also ductal differentiation. Thick bands of hyaline periodic acid-Schiff (PAS) stain and collagen IV-positive basement membrane material bordered the cell islands, and PAS-collagen IV-positive hyaline globules were seen within the cell islands. There was no nuclear pleomorphism or mitotic figures. The cylindroma did not express gross cystic disease fluid protein 15, carcinoembryonic antigen, estrogen and progesterone receptors, or cytokeratin 20 (CK20). There was diffuse and strong immunoreactivity to CK AE1/AE3, and focal reactivity for CK7 and smooth muscle actin. Cylindroma of the breast should be distinguished from adenoid cystic carcinoma and basal cell carcinoma. Although clearly epithelial, the exact histogenesis and cell phenotype of this unusual dermal type cylindroma of the breast are unknown.

The success of human kidney allotransplantation was realized over six decades ago. First described 50 years ago, renal autotransplantation has been utilized sparingly as a salvage procedure for patients at risk of losing renal function, either from a benign or malignant condition. While classically associated with colorectal malignancies, Lynch syndrome also carries a small yet significant risk for the development of ureteral carcinoma. For these patients who develop chronic kidney disease, allotransplantation may not be an option due to the lifelong risk of several malignancies. We report the first known case of renal autotransplantation in a patient with metachronous ureteral cancer due to Lynch syndrome.