Intranuclear Cytoplasmic Inclusions Research Articles

Dopaminergic loss and inclusion body formation in alpha-synuclein mice: implications for neurodegenerative disorders.

To elucidate the role of the synaptic protein alpha-synuclein in neurodegenerative disorders, transgenic mice expressing wild-type human alpha-synuclein were generated. Neuronal expression of human alpha-synuclein resulted in progressive accumulation of alpha-synuclein-and ubiquitin-immunoreactive inclusions in neurons in the neocortex, hippocampus, and substantia nigra. Ultrastructural analysis revealed both electron-dense intranuclear deposits and cytoplasmic inclusions. These alterations were associated with loss of dopaminergic terminals in the basal ganglia and with motor impairments. These results suggest that accumulation of wild-type alpha-synuclein may play a causal role in Parkinson's disease and related conditions.

Nuclear findings of ovarian surface epithelial tumors

While cytoplasmic features of ovarian surface epithelial tumors are well-known, the nuclear findings have received little attention. We reviewed imprint cytology materials of the ovary which were collected at the Kawasaki Medical School Hospital between January 1989-July 1999, and identified 15 mucinous cystadenomas, 3 borderline mucinous tumors, 4 mucinous cystadenocarcinomas, 4 serous cystadenomas, 4 borderline serous tumors, 7 serous cystadenocarcinomas, 6 endometrioid carcinomas, and 2 clear-cell adenocarcinomas. We microscopically observed nuclear findings of the 45 cases. Coffee-bean nuclei were observed in 15.0%, 15.8%, and 10.1% of the tumor cells in mucinous adenomas, borderline mucinous tumors, and borderline serous tumors, respectively. The frequencies of the coffee-bean nuclei in the three tumors were higher than in the remaining tumors (P < 0.001). Intranuclear cytoplasmic inclusions were observed in 2.1% of the tumor cells in mucinous cystadenoma, and their frequency was significantly higher than that in cases of other surface epithelial ovarian tumors (P < 0.001). Semilunar-shaped nuclei were seen in all cases of mucinous cystadenomas and borderline mucinous tumors, and in 3 of 4 mucinous adenocarcinomas. The remaining surface epithelial tumors did not reveal the semilunar-shaped nuclei. In the cytology of the ovary, the semilunar nuclei are characteristic of mucinous tumors, and the intranuclear cytoplasmic inclusion may be a diagnostic clue to mucinous cystadenoma, when it is conspicuous. The coffee-bean nuclei can be seen in mucinous cystadenoma, borderline mucinous tumors, and borderline serous tumors.

Cytopathology of papillary oncocytic carcinoma of the thyroid in fine-needle aspiration biopsy

The fine-needle aspirates from two histologically, immunohistochemically, and ultrastructurally confirmed encapsulated papillary oncocytic carcinoma of the thyroid revealed large and small papillary tumor tissue fragments consisting of fibrovascular cores covered with polygonal cells showing abundant and granular cytoplasm and small, oval nuclei. Abundant single and loosely clustered tumor cells with similar cytologic features were also present. Nuclear pleomorphism, irregular nuclear contours, nuclear grooves, and intranuclear cytoplasmic inclusions were not observed in any tumor cells. The two patients were alive and well and showed no evidence of tumor recurrence and/or metastatic disease 6 and 8 years after their thyroid surgeries, respectively.

Intranuclear Cytoplasmic Inclusions and Nuclear Grooves in Pleomorphic Adenoma of Parotid Gland

Diagnostic CytopathologyVolume 21, Issue 6 p. 435-436 Letter to the Editor Intranuclear Cytoplasmic Inclusions and Nuclear Grooves in Pleomorphic Adenoma of Parotid Gland Maria Sironi M.D., Maria Sironi M.D. Department of Pathology, Azienda G. Salvini, Ospedale Santa Corona, Garbagnate Milanese, ItalySearch for more papers by this authorRossella Claren p.M.I.A.C., Rossella Claren p.M.I.A.C. Department of Pathology, Azienda G. Salvini, Ospedale Santa Corona, Garbagnate Milanese, ItalySearch for more papers by this authorMaria Santangelo M.D., Maria Santangelo M.D. Department of Pathology, Azienda G. Salvini, Ospedale Santa Corona, Garbagnate Milanese, ItalySearch for more papers by this authorMaurizio Spinelli M.D., M.I.A.C., Maurizio Spinelli M.D., M.I.A.C. Department of Pathology, Azienda G. Salvini, Ospedale Santa Corona, Garbagnate Milanese, ItalySearch for more papers by this author Maria Sironi M.D., Maria Sironi M.D. Department of Pathology, Azienda G. Salvini, Ospedale Santa Corona, Garbagnate Milanese, ItalySearch for more papers by this authorRossella Claren p.M.I.A.C., Rossella Claren p.M.I.A.C. Department of Pathology, Azienda G. Salvini, Ospedale Santa Corona, Garbagnate Milanese, ItalySearch for more papers by this authorMaria Santangelo M.D., Maria Santangelo M.D. Department of Pathology, Azienda G. Salvini, Ospedale Santa Corona, Garbagnate Milanese, ItalySearch for more papers by this authorMaurizio Spinelli M.D., M.I.A.C., Maurizio Spinelli M.D., M.I.A.C. Department of Pathology, Azienda G. Salvini, Ospedale Santa Corona, Garbagnate Milanese, ItalySearch for more papers by this author First published: 24 November 1999 https://doi.org/10.1002/(SICI)1097-0339(199912)21:6<435::AID-DC15>3.0.CO;2-0Citations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume21, Issue6December 1999Pages 435-436 RelatedInformation

Solitary Nodular Goiter

To study the cytomorphologic features of solitary nodular goiters (SNG). May-Grünwald-Giemsa-stained smears in 441 SNG diagnosed by ultrasonography and fine needle aspiration (FNA) and found to have optimum cellular material at review were subjected to detailed cytologic assessment. The age of the patients ranged from 11 to 75 years, with a median of 35. Male: female ratio was 69:372. The parameters for cytologic assessment included cellularity, colloid content, acinar formation, papillary formation, intranuclear cytoplasmic inclusions, nuclear grooves, marginal vacuoles, Hürthle cells and various inflammatory cells. Histopathology reports on thyroidectomy specimens were available in 27 cases from two Delhi hospitals. Hyperplastic nodules (68 cases) differed significantly from colloid goiters (269 cases) by having more cases with excessive cellularity, acinar formation and marginal vacuoles (P < .001). There was also a significant difference with respect to papillary formation and moderate-to-excessive colloid content (P < .001). As compared to hyperplastic nodules, neoplasms (60 cases) had a significantly higher number of cases with papillary formation, intranuclear inclusions and nuclear grooves but lower number of cases with marginal vacuoles (P < .01-.001). Among neoplasms, usual papillary carcinoma (19 cases) differed from follicular neoplasms (20 cases) with respect to acinar formation, papillary formation and nuclear grooves (P < .001). A significant difference was also observed with respect to colloid content and nuclear inclusions. Follicular variant of papillary carcinomas (FVPC) (10 cases) emerged as a distinct cytologic entity following review and differed from usual papillary carcinomas in having a higher number of cases with acinar formation, tubular formation and marginal vacuoles (P < .01-.001) and lower number of cases with nuclear grooves (P = .05). FVPC also differed from follicular neoplasms with respect to papillary formation, tubular formation, intranuclear inclusions and nuclear grooves (P < .01-.001). Overall cytohistologic agreement was achieved in 24 of 27 (88.9%) cases. Detailed cytologic assessment of FNA smears-in SNG was helpful in highlighting parameters that differentiate between various types of goiters.

Fine-needle aspiration biopsy cytology of hyalinizing trabecular adenomas of the thyroid.

Cytologic smears from fine-needle aspirates of three histologically and ultrastructurally confirmed hyalinizing trabecular adenomas of the thyroid (HTAT) were reviewed. In two cases a cytodiagnosis of HTAT was suggested, and in one patient a diagnosis of trabecular epithelial neoplasm was made. In all three cases, small clusters and sheets of epithelial cells with abundant, filamentous, vacuolated, and ill-defined cytoplasm were present. The nuclei were slightly pleomorphic and showed nuclear overlapping, nuclear grooves, and intranuclear cytoplasmic inclusions. Small and irregular fragments of acellular hyalinized material (AHM) were noted within the tumor cell clusters in the first two cases. In the third patient, large syncytial sheets and anastomotic cords of epithelial cells showing ill-defined, filamentous cytoplasm, slightly pleomorphic nuclei, nuclear overlapping, intranuclear cytoplasmic inclusions, and nuclear grooves were present. Fragments of AHM were not observed within clusters and syncytial sheets of tumor cells.

核内細胞質封入体，核溝を伴った甲状腺好酸性細胞型腺腫の１例

We report a case of oxyphilic cell adenoma of the thyroid gland in a 79-year-old female. Fine needle aspiration cytology revealed isolated or sheetly-arranged tumor cells which had abundant eosinophilic granular cytoplasm. Eccentric nuclei showed intranuclear cytoplasmic inclusions and grooves. Histologically, a follicular adenoma, oxyphilic cell type was well-encapsulated and did not show vascular invasion or metastasis.

Fine-needle aspiration diagnosis of the follicular variant of papillary carcinoma

The follicular variant of papillary carcinoma (FVPC) presents significant diagnostic difficulty using fine-needle aspiration (FNA). Diagnoses by FNA vary considerably and usually are categorized as follicular proliferations. Conventional Papanicolaou, Diff-Quik, and hematoxylin and eosin stained FNAs from 16 cases of histologically confirmed FVPC were examined retrospectively. Each case was evaluated with respect to easily recognizable architectural and cytologic features. These were defined, ranked, and recorded for side-by-side comparison and identification of statistical significance. Similar features in six follicular carcinomas, seven follicular adenomas, and six adenomatous multinodular goiters were evaluated and compared as well. Eight of 16 FVPC cases (including 5 macrofollicular variants) previously were diagnosed on FNA as a follicular neoplasm or follicular lesion, 6 were diagnosed as a papillary carcinoma or FVPC, and the remaining 2 were diagnosed as atypical. The cellularity and amount of colloid varied considerably between cases. Monolayered, twisted epithelial sheets and microfollicles or macrofollicles were the predominant microarchitecture. Powdery chromatin and easily identifiable nuclear grooves were present in 15 cases (94%), and intranuclear cytoplasmic (INC) inclusions were present in 11 cases (69%). These three features proved to be statistically significant in distinguishing FVPC from the other follicular lesions. No case exhibited true papillary clusters or psammoma bodies. Cases of follicular adenoma, follicular carcinoma, and adenomatous goiter shared many of these features, but notably lacked INC inclusions and abundant nuclear grooves. Nuclear features such as abundant grooves, powdery chromatin, and INC inclusions were statistically significant and present in combination in the majority of cases of FVPC compared with the other follicular proliferations examined.

Intranuclear cytoplasmic inclusions in gastric leiomyosarcoma

Diagnostic CytopathologyVolume 18, Issue 6 p. 475-476 Letter to the Editor Intranuclear cytoplasmic inclusions in gastric leiomyosarcoma Tadao K. Kobayashi PH.D., C.F.I.A.C., Corresponding Author Tadao K. Kobayashi PH.D., C.F.I.A.C. Department of Cytopathology, Saiseikai Shiga Hospital, Imperial Gift Foundation, Inc., Ritto, Shiga, JapanDepartment of Cytopathology, Saiseikai Shiga Hospital, Imperial Gift Foundation, Inc., Ritto, Shiga, JapanSearch for more papers by this authorMakoto Katoh M.D., Makoto Katoh M.D. Department of Surgery, Saiseikai Shiga Hospital, Imperial Gift Foundation, Inc., Ritto, Shiga, JapanSearch for more papers by this authorShinsuke Watanabe M.D., PH.D., Shinsuke Watanabe M.D., PH.D. Department of Surgery, Saiseikai Shiga Hospital, Imperial Gift Foundation, Inc., Ritto, Shiga, JapanSearch for more papers by this authorChiyuki Kaneko PH.D., C.F.I.A.C., Chiyuki Kaneko PH.D., C.F.I.A.C. Division of Pathological Cytology, Institute for Comprehensive Medical Science, Fujita Health University School of Medicine, Toyoake, Aichi, JapanSearch for more papers by this author Tadao K. Kobayashi PH.D., C.F.I.A.C., Corresponding Author Tadao K. Kobayashi PH.D., C.F.I.A.C. Department of Cytopathology, Saiseikai Shiga Hospital, Imperial Gift Foundation, Inc., Ritto, Shiga, JapanDepartment of Cytopathology, Saiseikai Shiga Hospital, Imperial Gift Foundation, Inc., Ritto, Shiga, JapanSearch for more papers by this authorMakoto Katoh M.D., Makoto Katoh M.D. Department of Surgery, Saiseikai Shiga Hospital, Imperial Gift Foundation, Inc., Ritto, Shiga, JapanSearch for more papers by this authorShinsuke Watanabe M.D., PH.D., Shinsuke Watanabe M.D., PH.D. Department of Surgery, Saiseikai Shiga Hospital, Imperial Gift Foundation, Inc., Ritto, Shiga, JapanSearch for more papers by this authorChiyuki Kaneko PH.D., C.F.I.A.C., Chiyuki Kaneko PH.D., C.F.I.A.C. Division of Pathological Cytology, Institute for Comprehensive Medical Science, Fujita Health University School of Medicine, Toyoake, Aichi, JapanSearch for more papers by this author First published: 07 December 1998 https://doi.org/10.1002/(SICI)1097-0339(199806)18:6<475::AID-DC20>3.0.CO;2-DCitations: 2AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume18, Issue6June 1998Pages 475-476 RelatedInformation

Intranuclear cytoplasmic inclusions in the differential diagnosis of papillary thyroid carcinoma and bronchioloalveolar carcinoma

Intranuclear cytoplasmic inclusions in the differential diagnosis of papillary thyroid carcinoma and bronchioloalveolar carcinoma

Cytodiagnosis of metastatic amelanotic melanomas by fine-needle aspiration biopsy

The cytologic diagnosis (CD) of metastatic amelanotic melanomas (MAM) is challenging because the tumor cells may mimic those of a carcinoma or a sarcoma in cytologic materials obtained by fine-needle aspiration biopsy (FNAB). Thirty-five well documented cases of MAM at different anatomic sites with cytologic evaluation by FNAB were reviewed. In 31 cases a correct CD was made based on the cytologic and immunocytochemical (IM) findings. The MAMs were characterized by abundant dyshesive pleomorphic malignant cells containing prominent nucleoli and occasional intranuclear cytoplasmic inclusions. The tumor cells stained positively with S-100 and/ or HMB-45 antibodies. There were four cases with unusual cytologic manifestations and equivocal IM characteristics requiring electron microscopic examination (EME) of the aspirated tumor cells to identify intracytoplasmic melanosomes, pre-melanosomes, or microtubules within cisternae of rough endoplasmic reticulum (MCRER) to establish a diagnosis of MAM. A correct CD of MAMs may be made in a large number of cases by routine cytologic findings and IM staining with S-100 protein and HMB-45 antibodies. However, EME is necessary to demonstrate melanosomes, premelanosomes, or MCRER in cases with unusual cytologic and equivocal IM manifestations.

Atypical adenoma of the parathyroid gland. A case report.

Background: Atypical parathyroid adenoma is a borderline neoplasm defined by histological findings, while its cytological characteristics have not been described so far.Case: A 43-year-old man was diagnosed as primary hyperparathyroidism due to parathyroid tumor by medical check-up as a momentum. Although the extirpated tumor was welldemarcated by fibrous capsule, a few small tumor nests were observed in the capsule, which fulfilled the histological diagnostic criteria of atypical adenoma. Some of the tumor cells had giant and/or hyperchromatic nuclei, with intranuclear cytoplasmic inclusions in part, which may be used in favor of an estimation of adenoma rather than carcinoma. In addition, there were few mitotic figures in the tumor tissue and Ki-67 labeling index was as low as that in the conventional parathyroid adenomas.Conclusion: It is suggested that the present case is biologically akin to the conventional adenoma and that nuclear atypy and low proliferative activity are useful findings to estimate parathyroid neoplasms to be benign in the cytological specimens.

Primary melanoma of the lung: a clinicopathologic and immunohistochemical study of eight cases.

Primary malignant melanoma of the lung (PMML) is an uncommon neoplasm that may be confused with more conventional types of lung cancer. Although the previously proposed criteria for diagnosis, including the presence of an in situ component, are often difficult to satisfy, this lesion is characterized by a poor prognosis, ultimately leading to patient death. We report eight cases of PMML that presented as solitary, central endobronchial neoplasms, resulting in a picture that closely resembled carcinoid tumor or poorly differentiated non-small-cell carcinoma of the lung. The mean age at diagnosis was 51 years (range 45-71). The patients included one woman and seven men. The histologic growth pattern varied from organoid to fascicular and included epithelioid to spindled cells with hyperchromatic to vesicular nuclei, prominent eosinophilic nucleoli, and abundant eosinophilic to clear cytoplasm with occasional intranuclear cytoplasmic inclusions. A bronchial in situ component was present in four cases. Initial interpretations included carcinoid tumor, non-small-cell carcinoma, and malignant melanoma. Melanin was present in all neoplasms on hematoxylin and eosin staining, although very focally in one case, and was Fontana-Masson positive in all cases. Immunohistochemically, diffuse strong positivity for S-100, HMB-45, and vimentin was present in all seven tumors tested. All seven tumors were negative for cytokeratin, CAM 5.2, and chromogranin. Ultrastructural examination of the eighth case showed dysmorphic premelanosomes but no neurosecretory granules. None of the patients had disseminated disease at presentation, and all patients underwent surgical resection (seven lobectomies and one excision). In this series, primary malignant melanoma of the lung was characterized by an aggressive postoperative course, with five patients dying of metastatic disease from 4 to 32 months after resection (median 14 months). Two patients are alive with metastatic disease at 4 and 30 months after surgery, and the eighth patient is alive with no evidence of disease 108 months after surgery at last follow-up. Metastatic melanoma was identified in various sites, including the lungs, adrenal glands, liver, mesentery, brain, and bone. The cases herein presented indicate that PMML should be included in the differential diagnosis of primary bronchial tumors.

Distinction between bronchioloalveolar carcinoma and hyperplastic pulmonary proliferations: a cytologic and morphometric analysis.

The objectives of this study were to identify key cytologic features for the morphologic differentiation of bronchioloalveolar carcinoma from reactive pulmonary proliferations, and to determine if morphometry of the cytologic specimens could provide additional data to distinguish the two processes. We analyzed 15 morphologic criteria in pulmonary cytologic specimens from 17 histologically proven cases of bronchioloalveolar carcinoma and 13 cases with reactive cellular changes and compared the findings using univariate analysis. This revealed four statistically significant features more commonly associated with bronchioloalveolar carcinoma: (i) predominance of two- and three-dimensional tissue fragments, (ii) tenacious intercytoplasmic connections between cells, (iii) intranuclear cytoplasmic inclusions, and (iv) paucity of multinucleated cellular forms. Morphometric measurement revealed significant differences between the mean of the nuclear area of benign reactive cells and that of the malignant cells. The utilization of these criteria is helpful to diagnose bronchioloalveolar carcinoma and to distinguish it from reactive pulmonary processes.

The oncocytic variant of papillary carcinoma of the thyroid: A clinicopathologic study of 15 cases

The oncocytic variant of papillary carcinoma of the thyroid represents an unusual neoplasm whose clinicopathological features and biological behavior have not been thoroughly characterized. We studied 15 cases of thyroid tumors predominantly composed of oncocytic (oxyphilic) cells that were characterized by showing the classical nuclear features of papillary carcinoma of the thyroid. Thirteen patients were women, and two were men; their ages ranged from 34 to 86 years. The tumors measured from 1 to 4 cm in diameter and were well circumscribed and confined to the thyroid gland in all cases except for one, in whom there was extrathyroidal local extension. Histologically, all tumors showed, at least focally, the formation of papillary structures; in 13 cases the papillary features were found to predominate or were admixed in equal proportion with a follicular pattern of growth, and in two the follicular growth pattern predominated and only abortive, small papillary structures could be found on extensive search. In all cases, the classical optically clear nuclei of papillary carcinoma were present throughout the lesions. Nuclear grooves and intranuclear cytoplasmic inclusions were also a prominent and constant component of these lesions. In 13 cases, the tumors showed the features of Hashimoto's or lymphocytic thyroiditis in the surrounding, uninvolved thyroid parenchyma. Follow-up of 1.2 to 13 years (median, 4.5 years) showed the development of cervical lymph node metastases 9 months after surgery in one case; the remainder of patients were alive and free of disease. Oncocytic papillary carcinoma seems to represent a distinctive morphological variant of carcinoma of the thyroid that in our experience does not appear to behave more aggressively than conventional papillary carcinoma. The frequent association of these tumors with autoimmune thyroiditis raises the possibility that the oncocytic changes may be pathogenetically related with the latter process. These tumors should be distinguished from benign and malignant Hurthle cell tumors and other oncocytic thyroid neoplasms that may follow a different biological behavior.

Percutaneous needle biopsy diagnosis of benign neurogenic neoplasms.

Preoperative diagnosis of benign neurogenic neoplasms (BNNs) provides useful information in guiding management. To assess the effectiveness of fine-needle aspiration (FNA) and needle core biopsy (NCB) in diagnosing schwannomas and neurofibromas, 40 percutaneous biopsies interpreted as BNNs or obtained from lesions subsequently shown by excision to be BNNs were reviewed. The 13 aspirates diagnostic of BNN revealed spindle cells arranged haphazardly in irregular tissue fragments and in parallel as elongated ropy fascicles, with a myxoid to fibrillary background. The nuclei were buckled, often with intranuclear cytoplasmic inclusions. Four lesions showed nuclear pleomorphism without mitoses. Of 19 schwannomas evaluated by FNA, four (21%) were diagnosed as schwannomas and seven (37%) as BNNs. Ten neurofibromas were aspirated, revealing two (20%) BNNs. Of seven nondiagnostic FNAs accompanied by NCB, three (43%) indicated a BNN. The sensitivities of FNA, NCB, and both modalities in diagnosing BNNs were 43,60, and 71%, respectively. For the 16 FNAs showing features of BNNs, subsequent excisions revealed 11 schwannomas, two neurofibromas, one neurogenic sarcoma, one fibromyxoid neoplasm of uncertain malignant potential, and one unclassified low-grade myxoid sarcoma. FNA can be effective in diagnosing BNNs. If collagenous or myxoid lesions yield paucicellular nondiagnostic aspirates, NCB is helpful. Lowgrade sarcoma and neurofibromatous areas of neurogenic sarcoma may be misinterpreted as BNNs by percutaneous biopsy. BNNs may show nuclear pleomorphism without mitotic activity, and should not be mistaken for sarcoma.

Presumption of primary sites of neck lymph node metastases on fine needle aspiration cytology.

To evaluate the accuracy of presumption of the primary sites of neck lymph node metastases based on fine needle aspiration cytology. Retrospective review of 133 cytologically diagnosed carcinomas with known primary sites and sufficient cellularity during a three-year period. Presumption of primary sites was carried out on randomized samples six months later. Some cytomorphologic characteristics are useful for presumption of primary sites, such as monolayered papillary fronds with intranuclear cytoplasmic inclusions in thyroid papillary carcinoma; large, polygonal, keratinized cells with a low nuclear/cytoplasmic ratio and anucleated squames in perioral cancers; and numerous naked nuclei, destroyed nuclei and marked lymphocytic infiltrates in nasopharyngeal cancer. The accuracy rate of presumption of primary sites was 100% (6/6) in thyroid papillary carcinoma, 83% (24/29) in perioral cancer and 77% (26/34) in nasopharyngeal cancer but low in other malignancies. Utilizing cytomorphologic characteristics, a presumption of primary sites of neck lymph node metastases could be achieved for the thyroid, perioral areas and nasopharynx.

Pleomorphic hyalinizing angiectatic tumor of soft parts. A low-grade neoplasm resembling neurilemoma.

Fourteen examples of an unusual mesenchymal tumor characterized by sheets and fascicles of mitotically inactive, hemosiderin-stippled, spindled, and pleomorphic cells, situated around an angiectatic vasculature, are described. The 14 tumours developed in eight women and six men (aged 32-83 years) and ranged in size from 2.3 to 8 cm. Eleven cases presented in the subcutaneous tissues, of which eight were located in the lower extremity. All featured prominent clusters of thin-walled ectatic vessels surrounded by perivascular hyaline material representing a combination of fibrin and collagen. In three cases the perivascular hyalinization was so extensive that it constituted more than half of the total tumor area. The tumor cells were similar to those of malignant fibrous hystiocytoma but differed from them by the presence of prominent intranuclear cytoplasmic inclusions, the extreme scarcity of mitotic figures, and the occasional presence of CD-34 expression. These tumors also shared several features with neurilemomas, such as their unusual vasculature, intranuclear cytoplasmic inclusions, lack of mitotic figures, and abundance of mast cells. They could be distinguished from neurilemomas, however, by the usual presence of infiltrative margins and the absence of S-100 protein. Follow-up information on eight patients (6 months to 25 years) indicated recurrences in four cases, with one of the three patients experiencing numerous recurrences over a 25-year period. No patient has developed metastases, however. We suggest that this tumor is a low-grade sarcoma of uncertain lineage in which the vascular changes are, in part, reflective of its slow growth.

Fine Needle Aspiration and Frozen Section Diagnosis in the Management of Thyroid Nodules

Fine needle aspiration (FNA) is a valuable technique in the evaluation of thyroid nodules. A total of 182 FNAs of the thyroid performed at the Sultan Qaboos University Hospital were reevaluated and 153 were found to be adequate (84%). The cytological results of FNA were divided into neoplastic and non-neoplastic groups. Subsequent histology was obtained in 53 patients with an intraoperative frozen actions (FS) in 27 patients. Papillary carcinoma was found to be the most common, accounting for 70% of these cases with histological follow-up in the neoplastic group. The utility of performing FNA in all thyroid nodules and an intraoperative frozen section only in selected cases is discussed.

Peculiar nuclear clearing composed of microfilaments in papillary carcinoma of the thyroid

Papillary carcinoma of the thyroid frequently occurs in young women. Four cases of papillary carcinoma were found in women in their 20s, and the disease was characterized by unusual morphologic and clinical features.Four cases were analyzed clinically, grossly, microscopically, ultrastructurally, and immunohistochemically and compared with control cases of papillary carcinoma.The tumors histologically showed various appearances with trabecular, solid cribriform, follicular, and papillary patterns. A striking finding was that stratified cancer cell nests with prominent nuclear clearings were scattered in the tumors. Ultrastructurally, the nuclear clearings were composed of fine thread-like fibrils, and they were bound unselectively to various antibodies against hormones and intermediate filaments. The four patients also had common clinicopathologic features as follows: they were all women in their 20s and their preoperative serum thyroglobulin levels were all normal despite the large size of their thyroid tumors. The tumors were grossly well encapsulated, and there was no lymph node metastasis, except in one patient who had only one positive node.The peculiar nuclear features were distinct from intranuclear cytoplasmic inclusions or ground-glass nuclei, and these have not been reported previously to the authors' knowledge in conventional thyroid neoplasms. These tumors might represent another subtype of papillary thyroid carcinoma.