Primary leiomyosarcomas of the gastrointestinal tract in the post-gastrointestinal stromal tumor era.

Most mesenchymal neoplasms of the gastrointestinal tract are currently classified as gastrointestinal stromal tumors (GIST). Gastrointestinal stromal tumors are diagnosed by immunopositivity for CD117, CD34, and DOG1.1, with or without molecular analyses. According to the World Health Organization classification, the diagnosis of primary leiomyosarcomas of the gastrointestinal tract is so rare that there are no significant data on demographic, clinical, or gross features of this tumor. A comprehensive literature search was performed to identify gastrointestinal leiomyosarcomas. Searches were limited to the past 12 years because definitive tools to differentiate leiomyosarcomas from GIST were introduced in the late 1990s. Cases were included only if convincing data were presented. Six cases of esophageal leiomyosarcoma and 5 cases of gastric leiomyosarcoma were confirmed. Furthermore, 26 cases of leiomyosarcoma of the small bowel, 11 cases of the colon, and 8 cases arising in the rectum were identified. Finally, 28 cases of infantile and adolescent leiomyosarcoma were reviewed. Although survival analysis is precluded by small case numbers and limited survival data availability, the trend identifies that increased size and mitotic activity portends to a worse prognosis in small bowel leiomyosarcomas. Colonic leiomyosarcomas appear to be aggressive tumors, regardless of tumor size and mitotic activity. Rectal leiomyosarcomas present as smaller tumors with favorable prognosis. Leiomyosarcomas in post-GIST era are rare tumors of the gastrointestinal tract with distinctive clinicopathologic characteristics. Owing to different treatment options, it is necessary to accurately differentiate these from GIST, using a combination of histologic appearance, presence of smooth muscle antigens, and absence of specific GIST immunomarkers.

The cytologic findings in choroid plexus carcinoma: report of a case with differential diagnosis.

Choroid plexus carcinoma is a rare tumor of the choroid plexus that shows frank cytologic features of malignancy including frequent mitoses, increased cellularity, nuclear pleomorphism, loss of papillary architecture, and necrosis. It occurs predominantly in the pediatric population and is associated with a poor prognosis. We report the cerebrospinal fluid and intraoperative squash preparation cytologic findings of a case of choroid plexus carcinoma arising in the lateral ventricle of a 16-year-old girl who developed tumor recurrence in cerebrospinal fluid 6 years after initial resection. To the best of our knowledge, there are only a few reports in the English literature describing the cytologic features of choroid plexus carcinoma. Relevant differentials and the usefulness of ancillary studies in diagnosis are also discussed.

Liquid-based pap smears as a source of RNA for gene expression analysis.

The Papanicolaou smear has contributed to a decrease in cervical cancer rates in populations that receive regular screening. However, treatment of women with mildly abnormal cells is problematic because the majority of these women do not develop neoplasia. Thus, new techniques for identification of truly precancerous cells are needed. Characterization of cellular gene expression patterns is now possible through microarray techniques that survey the expression of large numbers of genes simultaneously. Here we have assessed the feasibility of combining new microscopic and molecular technologies to determine gene expression patterns in cervical intraepithelial neoplasia grade 3 cells recovered from liquid cytology-based Papanicolaou smear slides. Laser capture microdissection was used to retrieve cervical cells from ThinPrep prepared slides. The quality of RNA recovered from these cells proved suitable for reverse transcription polymerase chain reaction and for T7 RNA polymerase-based linear amplification of messenger RNA. We developed an optimized RNA amplification protocol that permitted microarray gene expression profiling in samples of as few as 20 cervical cells. This approach combining laser capture microdissection, linear RNA amplification, and microarray gene expression analysis will enable comparison of gene expression patterns between cytologically abnormal and normal cells taken from a single slide and may assist in the differential diagnosis of histologically difficult cases.