Pulmonary Lymphangioleiomyomatosis: A Case Report and Literature Review.

Pulmonary lymphangioleiomyomatosis (LAM) is a rare lung disease characterized by diffuse cystic changes caused by a destructive proliferation of smooth muscle-like cells or LAM cells. It is a part of the perivascular epithelioid cell family of tumors. LAM may be associated with the genetic disorder tuberous sclerosis complex or may occur sporadically. Individuals affected by LAM are typically females of child-bearing age who present with recurrent spontaneous pneumothorax. The microscopic findings can be subtle and careful examination is needed to identify the neoplastic cells of LAM. Immunohistochemical markers in cases of LAM demonstrate a characteristic co-expression of myogenic and melanocytic markers. We report a case of a 41-year-old woman who presented with multiple episodes of spontaneous pneumothorax and microscopic findings characteristic of LAM.

Loss of Mismatch Repair Protein Expression in Unselected Endometrial Adenocarcinoma Precursor Lesions.

OBJECTIVE: The benefit of evaluating the precursor of endometrial carcinoma, endometrial hyperplasia (intraepithelial neoplasia [EIN]), for loss of mismatch repair (MMR) protein expression and Lynch syndrome has yet to be determined. The present study aims to establish the incidence and type of loss of MMR protein expression in unselected premalignant lesions of endometrial adenocarcinoma, as well as the agreement of immunohistochemical staining in pretreatment endometrial biopsy (EMB) specimens with subsequent uterine resections. METHODS: A retrospective review identified 112 endometrial biopsies meeting criteria for endometrial EIN. Slides made from tissue microarray blocks were evaluated using antibodies against MLH1, PMS2, MSH2, and MSH6. Cases with a deficit in MLH1 were evaluated for gene promoter hypermethylation by polymerase chain reaction analysis. Fifty-four subsequent hysterectomy specimens were retrieved and assessed for MMR protein expression. RESULTS: Of the 112 endometrial biopsies with EIN, 4.5% (5/112) exhibited loss of MMR protein expression. The majority (4/5) demonstrated a deficit of MLH1, of which all exhibited inactivation via promoter hypermethylation. A single case displayed an absence of MSH6. Age was not significantly associated with MMR deficiency. There was no significant association between MMR status in the EMB and a subsequent diagnosis of cancer. Immunohistochemical staining in all successive hysterectomy cases was concordant with the pattern observed in the EMB specimen. CONCLUSIONS: Sporadic hypermethylation of MLH1 seems to be the primary mechanism underlying defective MMR protein expression in EIN. Among our cohort, only 1 patient (<1%) had a mutation suggestive of a hereditary inheritance. Hence, the utility of evaluating EIN for MMR protein expression as a screen for Lynch syndrome is limited, regardless of age.