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BACKGROUND Gain‐of‐function mutations of the c‐kit protooncogene, mainly clustered in the juxtamembrane domain, have been reported in a significant fraction of gastrointestinal (GI) stromal tumors (GISTs) that represent the most common mesenchymal tumor of the GI tract. Two families also have been described with a GIST predisposition syndrome with a germline c‐kit mutation affecting either the juxtamembrane domain or the tyrosine kinase domain. Here, the authors report on a family in which the dominantly inherited trait of hyperpigmented spots was inherited from an individual who developed multiple GISTs with diffuse hyperplasia of the myenteric plexus by his son, who was affected with urticaria pigmentosa. METHODS Screening for the c‐kit mutation was performed by means of polymerase chain reaction‐based denaturing gradient gel electrophoresis/constant denaturing gel electrophoresis followed by direct sequencing of abnormal conformers. Expression of KIT and CD34 was determined by immunohistochemistry. RESULTS In peripheral blood DNA samples, both affected family members showed a previously undescribed c‐kit mutation in the juxtamembrane domain, resulting in the substitution of alanine for valine559. Mutation and polymorphic marker analyses on DNA samples from three GISTs and two skin biopsy specimens evidenced the same mutation in the heterozygous condition. Immunohistochemical examination showed coexpression of CD117 (c‐kit) and CD34 in all independent GISTs and CD117 positivity in mast cells from the skin lesions. CONCLUSIONS Comparative analysis of clinical presentation and mutation mapping in the families described to date point to the peculiar association of mast cells, melanocytic dysfunction, and GIST predisposition in carriers of c‐kit mutations within the juxtamembrane domain. Cancer 2001;92:657–62. © 2001 American Cancer Society.

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Our study confirmed the great efficacy of thyroid FNAC. A cytological diagnosis of Hurthle cell neoplasm should be considered an indicator of high risk. Awareness that failure to recognize the follicular variant of papillary carcinoma was the main problem in the interpretation of thyroid FNAC should lead to a decrease of false-negative diagnoses. The inadequate rate was very low, as it was the pathologist personally who performed the needle aspiration.

Between 1980 and 1998, 4272 thyroid surgical specimens with a preoperative fine needle aspirate were sent to our Anatomical Pathology Department. Among these cases there were 17 primary thyroid lymphomas, which constituted 0.3% of all the thyroid lesions and 2.3% of the thyroid malignancies. Seven cases were diffuse large B-cell (DLBC) lymphomas and 10 were MALT lymphomas. Of the DLBC lymphomas six were correctly diagnosed by fine needle aspiration cytology (FNAC) and one was diagnosed as positive for malignancy, and among MALT lymphomas four were diagnosed as lymphoma, four as suspicious for lymphoma, and three as Hashimoto's thyroiditis (HT). Our data indicate that the diagnosis of primary thyroid lymphoma of high grade is easy, and immunocytochemistry (ICC) can confirm suspicious cases. The diagnosis of MALT lymphoma is more difficult; ICC can confirm suspicious cases, and false-negative results seem to be caused by sampling error, because HT usually coexists with MALT lymphoma.

We report here on five new cases of solid and cystic papillary neoplasm (SCPN) of the pancreas diagnosed by fine-needle aspiration cytology (FNAC). All cytologic samples were obtained by ultrasonography, and the smears were conventionally fixed and stained. Special histochemical and immunocytochemical stains were also performed in some samples. Cytology revealed in all but one case numerous pseudopapillary structures composed of fibrovascular stalks lined with one or more layers of bland-appearing, uniform tumor cells. The tumor cells had round-to-oval euchromatic nuclei with frequently folded smooth contours and one or two small nucleoli. Their cytoplasm often contained eosinophilic, PAS-positive, and diastase-resistant inclusions. Foamy cells, psammoma bodies, blood, and cellular debris were found in the background. The criteria for the differential diagnosis versus other pancreatic lesions are discussed in some detail, as is the role of immunocytochemistry (ICC). In the literature, only 28 cases of cytologically investigated SCPN have been reported to the best of our knowledge. The most helpful criteria for the conclusive identification of SCPN by FNAC include the pseudopapillary arrangement with bland-appearing tumor cells, and, especially, the finding of acidophilic, PAS-positive, and diastase-resistant cytoplasmic granules.

CP is a safe technique for benign or low-grade malignant tumours of the pancreatic neck that allows one to cure the tumour with evident functional results without increasing the risk to the patient.