Objective: We retrospectively studied the cytological characteristics of large cell neuroendocrine carcinoma (LCNEC) of the lung, classified in the new WHO classification.
Study Design: We reviewed 24 specimens of LCNEC obtained by stamp preparation and stained by Papanicolaou's method.
Results: Accompanying necrotic debris in the background, tumor cells were dyscohesive and singly dispersed or formed small clusters. In the area of single cell scatter, tumor cells were stripped and degenerative. Many showed rosette-like formations. Tumor cells had pale cytoplasm and a small to middle-sized nucleus that was round to oval, and sometimes slightly elongated, and whose margin was thin and smooth. Nuclear chromatin was finely granular and evenly distributed, and a nucleolus was prominent. In a few cases, we observed mitosis-like features but it was difficult to differentiate these from those of necrotic or degenerative cells.
Conclusion: LCNEC showed characteristic cytological features, but individual findings may also be observed in other neuroendocrine tumors such as atypical carcinoid or small-cell carcinoma. It is thus necessary to examine cytological characteristics of LCNEC in brush or sputum specimens, and to compare them with other neuroendocrine tumors and poorly differentiated adenocarcinoma or squamous cell carcinoma.

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Objectives: Many specimens are inadequate or unsatisfactory for cytologic evaluation in FNAC of the breast. From Jan. 1988 to Dec. 1995, we studied 2, 797 FNAC involving 2, 106 breast tumors at Sanikukai Hospital. The 314 Inadequate Specimens were divided into 2 groups Scant Cellularity (SC) and Failure in Fixation and/or Staining (FFS). We analyzed causes of SC and how to decrease SC incidence.
Study Design: To determine the causes of SC in aspirates, we studied the incidence of SC of each doctor who practised FNAC, and analyzed the relationship between cases of SC and their histologic types.
Results: SC occurred in 284 cases (10.2% of all aspirates). Incidence per doctor differed from 1.0% to 35.8%, and was closely related to skill in aspiration technique. Some histologic types of breast lesions, such as scirrhous carcinomas and mastopathies, were difficult to aspirate for adquate cytologic materials. In FNAC retrial for Inadequate Specimen in the first FNAC, the incidence of Inadequate Specimens decreased dramatically.
Conclusions: 1. The high incidence of SC were strongly related to poor aspiration by unskilled doctors and the histologic type of target tumors such as scirrhous carcinomas and masthopathies that consisted of dense fibrous tissues and few tumor cells. 2. Our recommendations in Inadequte Specimens are to repeat FNAC and/or do surgical biopsy. 3. In all reports of FNAC, Cytopathologist should note the Adequacy of the Specimen of aspirates.

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Objective: Cytological samples from patients with adenocarcinoma in situ (AIS) of the uterine cervix were analyzed for diagnostic criteria for glandular dysplasia (GD). GD has fewer diagnostic criteria in cytological specimens compared to squamous neoplasias.
Study Design: Three patients with AIS of the uterine cervix were studied pathoistologically using histological and cytological specimens. Histological specimens were obtained from resected cervix by cone biopsy and stained with H-E stain. Cytological specimens were obtained from the cervix by wooden scrapers before surgery and stained with Papanicolaou stain. In histological specimens, both AIS and GD lesions were recognized. In cytological specimens, both cells probably derived from AIS and GD were searched for based on their resemblance to AIS and GD cells in histological specimens. After finding these cells, cytological features of GD were analyzed by comparison with them. To study differences in GD and other benign lesions, cells probably derived from GD were categorized into 3 groups. Each group was compared to the cells from other benign lesions.
Results: The cells probably derived from AIS had all of the following findings: Nuclear stratification was marked, cellular arrangement was irregular, nuclear overlapping was marked, nuclear shape was irregular, and nuclear hyperchromasia was high or moderate. However, cells probably derived from GD lacked at least one of these findings and tended to have nuclear overlapping, enlargement, or elongation.
It was difficult to differentiate cells probably derived from GD that tended to have nuclear overlapping from microglandular hyperplasia and tissue repair cells and metaplastic cells. Cells that tended to have nuclear enlargement were different from benign cells because they had irregularly shaped nuclei, while it was easy to differentiate cells that tended to have nuclear elongation from benign cells because they were elongated and had enlarged, irregularly shaped nuclei.
Conclusions: Cells from GD lack at least 1 of the findings recognized in cells from AIS. According to nuclear atypia, cells from GD can be categorized into 3 groups. This classification is useful in differentiating cells from GD from those from other benign lesions.

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Objective: We examined the cytological features of adenocarcinoma in situ (AIS) of the uterine cervix to obtain findings for cytological diagnosis
Study Design: Well preserved Pap. smears from 8 AIS cases were examined cytologically and analyzed cytomorphologically compared to invasive adenocarcinoma and normal endocervical cells.
Results: In 6 of the 8 cases, the presence of AIS was indicated. Of the remaining 2, 1 showed minimal glandular atypia and the other squamous atypia.
A clean background with the coexistence of normal endocervical cells was observed in all cases. Although cells were aligned in irregular palisades, or a glandlike rossette formation, many single endocervical cells scattered throughout smears was a striking feature. Maximal nuclear diameter and nuclear area in AIS cells were larger than in normal endocervical cells, and but did not differ from those in invasive endocervical adenocarcinoma cells. The coefficient ariation was largest in AIS cells, suggesting the coexistence of normal endocervical cells and cells from glandular dysplasia in AIS cells.
Conclusion: A clean background with the coexistence of normal endocervical cells and many scattered single tumor cells appear to be cytologic features in AIS.

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Objective and Study Design: We evaluated the adequacy of all cytologic specimens from November 1996 to at our hospital. We discuss the importance of specimen adequacy evaluation, based on 3, 000 cervical specimens.
Results: (1) A considerable number of cervical specimens (34.3%) were unsatisfactory. The rate was higher in the postmenopausal women (41.4-48.8%) than in premenopausal (29.3-32.3%). The main cause was specimen drying.(2) Rates varied widely among the 5 gynecologists who made specimens: from 54.7% to 25.8%. The main cause was the unsatisfactory number of target cells.
Conclusions: (1) To achieve satisfactory cytodiagnosis of cervical specimens, it is now important to teach gynecologists to make satisfactory specimens: by obtaining a satisfactory number of target cells and avoiding drying (rapid smearing and immediate fixation).(2) As indicated above, the specimen adequacy evaluation is extremely important in quality management of cytodiagnosis and provides important clinical information ensuring the reliability of cytodiagnosis.

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Background: We report a case of mediastinal large B-cell lymphoma (MLBL) diagnosed by pleural effusion cytology.
Case: A 19-year-old man was referred to our hospital due to detection of an anterior mediastinal tumor, pleural effusion, and hyperlactate dehydrogenasemia.
Through our diagnosis with pleural effusion cytology and computed tomography (CT) guide biopsy for the anterior mediastinal tumor, we found that clover shaped nuclei and/or jointed thread-like nuclei similar to neutrophils lobated flatly from one point to other points in pleural effusion. We confirmed the presence of tumor cells in the form of multilobated nuclei.
The patient was diagnosed with MLBL based on a biopsy specimen taken from the anterior mediastinal tumor, which revealed diffuse proliferation of large atypical lymphoid cells with multilobated nuclei and sclerosis caused by hyperplasia of collagen fiber.
Conclusion: Since MLBL has a very specific nuclear feature, it can be diagnosed by cytology and close study of cytrography and clinical features.

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Background: Multilobated B-cell lymphoma (MLBL) is rare. We describe a case probably derived from a parapancreatic lymph node.
Case: A 37-year old Japanese man was hospitalized with suspected pancreatic cancer. Ascites cytology showed abundant medium to large atypical lymphocytes with marked nuclear indentation resembling a flower. More than half of the tumor cells had 3 or more lobed nuclei.
At autopsy, lymphoma cells immunohistochemically proven to have a B-cell phenotype were mainly found proliferating in parapancreatic lymph nodes with invasion to multiple organs. These finding confirmed this case to be MLBL, probably derived from a parapancreatic lymph node. Using ascites material and tumor tissue obtained at autopsy, immunoglobulin heavy chain gene rearrangement analysis demonstrated a single band, indicating monoclonal proliferation of B-cell lymphoma cells. Electron microscopy showed rough surface endplasmic reticulum, mitochondria, fat droplets, and microvilli-like structures in tumor cells.
Conclusions: It is important in diagnosing MLBL to detect characteristic nuclear findings. Immunoglobulin gene analysis and electron microscopy aid in such diagnosis.

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Background: We report an extremely rare case of primary malignant melanoma of the lung.
Case: A 35-year-old man was admitted to our hospital because of right shoulder pain. Bronchial brushing cytology showed sheet-like or loose clusters of tumor cells, with a granular nuclear chromatin pattern. Immunohistochemically, tumor cells were positive for S-100 protein, focally positive for HMB-45, and negative for cytokeratins.
Conclusion: Primary malignt melanoma of the lung is extremely rare. Immunohistochemical and/or electron microscopic studies are useful for the diagnosis of amelanotic malignat melanoma.

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Background: Intraabdominal metastasis of rhabdomyosarcoma is very rare. We presented a case of gluteal pleomorphic rhabdomyosarcoma with intraabdominal metastasis and discussed the disease course.
Case: A 28-year-old Japanese man was hospitalized because of painful swelling in the left gluteal region. Biopsy indicated a tumor diagnosed as pleomorphic rhabdomyosarcoma. After tumor resection, the patient was treated with chemotherapy. One year later, an intraabdominal tumor with ascites was found in computed tomography. Ascites cytology showed small clusters, sheets, and many individual large pleomorphic tumor cells with abundant vesicular cytoplasm. Tumor cells had granular hyperchromatic nucleiwith prominent nucleoli. Cross-striations in their cytoplasm were not observed. Immunohistochemical staining revealed that the tumor cells were positive for myoglobin, MyoD, and desmin.
Conclusion: Although hematogenous metastasis is common in most sarcomas, lymphogenous dissemination was considered in our case. Final diagnosis was difficult based on cytologic findings alone. Immunohistochemical staining is important in differentiating this tumor from other pleomorphic sarcomas.

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Background: The thyroid gland with chronic thyroiditis occasionally shows follicular epithelial cells with atypical nucleus that make it difficult to differentiate them frommalignant cells; in the diagnosis of multinodular thyroid lesions, we must consider the possible coexistence of benign and malignant lesions in the same thyroid gland.
Case: A 41-year-old woman with struma was admitted to our Surgery Division in December 1997. Computed tomography (CT) and ultrasonography suggested adenomatous goiter. Follow-up CT showed the lesion was growing and thyroid hormone values were increasing. Right subtotal thyroidectomy was conducted in March 2000. The resected specimen consisted of one large nodule and several smaller nodules. Intraoperative cytology from the large nodule was that of chronic thyroiditis. As for that from a smaller nodule, cell clusters showed a sheet-like and microfollicular appearance. These epithelial cells had enlarged, hyperchromatic nuclei with granular cytoplasm. The cells looked more atypical than those in ordinary cases of chronic thyroiditis, so the possibility of malignancy was suspected. However, the chromatin pattern of the nuclei looked so uniform that we could not decide if the cells were malignant.
Conclusion: When diagnosing such atypical epithelial cells as in this case, we should rule out oxyhilic cell follicular carcinoma. It is important to observe the chromatin pattern and cytoplasm precisely and lymphocytes in the background.

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Background: We describe the cytologic features of touch smears in 4 cases of histologically confirmed solid cystic tumor (SCT).
Cases: The 4 women were aged 12, 14, 30, and 31 years of age. Three had a capsule with a pseudocystic appearance with central necrosis. The fourth had no capsule and was solid without central necrosis. Cytologically, 3 cases showed uniform small tumor cells without atypia arranged papillarily in the hemorrhagic and necrotic background. The fourth showed scant viable cells with marked hemorrhagic necrosis and ghost-like cell clusters with a papillary structure.
Conclusion: Islet cell tumor, acinar cell carcinoma, and pancreatoblastoma show similar image findings, and should be differentiated from SCT. Cytologically, a papillary struc ture with a fibrovascular stalk seemed to be characteristic of SCT.

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Background: A large proportion of the fine needle aspiration (FNA) cases of the salivary glands consists of pleomorphic adenoma or mixed tumor, the most common salivary gland tumor. The cytological specimens of the typical mixed tumor show loosely connected epithelial cell clusters with myoepithelial cells streaming into the mucinous stromal components in the background. The stromal components show striking metachromatic staining under the May-Giemsa stain. In most cases diagnosis of the mixed tumor in FNA is easily made from these characteristic cytological findings. The mixed tumor, however, shows morphologic diversity and in some cases this hinders an accurate cytological diagnosis.
Study Design and Results: We classified the morphologic variations of the mixed tumor into seven patterns: 1) cellular mixed tumor with small myoepithelial cell proliferation; 2) cellular mixed tumor with spindle myoepithelial cell proliferation; 3) proliferation of plasmacytoid myoepithelial cells; 4) atypical myoepithelial cells; 5) squamous metaplasia; 6) hyaline stroma between myoepithelial cells; and 7) formation of pseudoglandular structures containing mucin. We discuss the differential diagnosis for each subtype.
Conclusions: The morphologic diversity of the mixed tumor must be carefully considered in the differential diagnosis based on FNA of the salivary glands.

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Objective: Significance of cytologic diagnosis of Warthin's tumor is re-evaluated in comparison with its histologic features.
Histology: Warthin's tumor is histologically characterized by cystic spaces lined by a papillary proliferation of bilayered oncocytic epithelium whose stroma is composed largely of follicle-containing lymhoid tissue. The cytoplasmic granularity of oncocytic epithelial cells is due to abundant mitochondria. Metaplastic squamous cells or goblet cells are occasionally seen. Cystic spaces are filled with mucoid material, degenerated oncocytes, necrotic debris, lymphocytes, cholesterin crystals, and so on.
Cytology: Fine needle aspiration cytology typically produces cystic fluid that may contain tissue fragments. When tissue fragments composed of both oncocytes and lymphocytes are revealed, diagnosis is not so difficult. However, a smear from Warthin's tumor often consists only of cystic contents. In such cases, it is crucial to find and recognize exfoliated oncocytes with degenerative change among necrotic debris or mucoid material. Metaplastic squamous cells should not be considered as squamous cell carcinoma.
Conclusion: Preopereteive recognition of Warthin's tumor by cytology is especically important because it may change the treatment strategy of the patient.

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Objective: Mucoepidermoid carcinoma is a tumor composed of variable proportions of mucus-producing, intermediate, squamous, and clear cells and represents a wide spectrum of malignant potential. A grading system that subtypes this tumor into low, intermediate, and high-grades according to cellular atypia and histological architecture has been generally accepted. We evaluted cytological appearance corresponding to these 3 grades.
Method: Cases capable of sufficient study, which arose in the parotid and intraoral minor salivary glands, were collected from the registry file of the Department of Pathology, Kurume University School of Medicine. All imprinted cytologic smears obtained in intraoperative rapid diagnosis procedure were stained with Papanicolaou, Giemsa, Peroidic acid Schiff, and Alcian blue stains.
Results: Neoplastic cells appeared forming loose, small clusters or isolated in the background between clusters. Squamous cells appeared more predominantly in high-grade cases, while mucus-producing and intermediate cells were valid in low-grade cases. Cytological atypia was remarkable in high-grade cases, which included pleomorphic undifferentiated cells and commonly lacked definable mucusproducing cells. No characteristic arrangement and little further difference between the 3 grades were recognized except in cell proportion, cytological, atypia and pleomorphism.
Comments: Important diagnostic problem lies in highgrade cases, in which occasionally mucin-production is hardly evident. Intermediated-or high-grade mucoepidermoid carcinoma should be considered when tumors predominantly consist of squamous cells, especially in major salivary glands, except with evident preexisting pleomorphic adenoma. In such an instance, In-2 type cells described by Kawahara et al.(1999) may be helpful for accurate diagnosis.

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Background: To observe cytological specimens of the salivary gland tumors, it is necessary to be familiar with histological findings. We describe cytologic findings of adenoid cystic carcinoma and compare them with histological findings.
Histological and Cytological Findings: Adenoid cystic carcinoma is classified into 3 histological types-cribriform, solid, and tubular. The cribriform type is the most characteristic of this tumor, and cytologically shows metachromatic balls in cell clusters and in the background. There are 2 types of balls-mucous, composed of transparent stromal mucin, and hyaline, composed of light-green-positive, basement membrane-like materials. Differential diagnoses of the cribriform type are basal cell adenoma, basal cell adenocarcinoma, cellular pleomorphic adenoma, polymorphous low-grade adenocarcinoma, and epithelial myoepithelial carcinoma. The solid type shows large clusters composed of small atypical cells remuiniscent of a jigsaw puzzle. Differential diagnoses of the solid type are small cell carcinoma and basaloid squamous cell carcinoma. The tubular type shows glandular or trabecular clusters, and it may be difficult to distinguish it from polymorphous low-grade adenocarcinoma.
Conclusion: It is well known that hyaline and mucinous balls are characteristic of adenoid cystic carcinoma, but they are not pathognomonic. Cytologically, we must distinguish adenoid cystic carcinoma from several salivary gland tumors.

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Objective: This report presents the cytological findings by growth pattern in acinic cell carcinoma.
Study Design: The cell images are examined for four growth patterns from which the histological diagnosis was determined.
Results: 1) Solid pattern: Cell clusters with an acinar structure or single tumor cells are observed. The nucleus is small and round with a slight increase of chromatin. The wide cytoplasm is faint and granular. The small nucleolus is clear.
2) Microcystic pattern: Small cells with vacuolated cytoplasm are observed in clusters. The tumor cells are similar in from to acini with a slightly atypical nucleous.
3) Papillary-cystic pattern: The smear consists of mainly papillary clusters, there are few single cells. The limbic cluster has an acinar structure. Psammoma bodies and vacuolated cells are frequently discovered on cytologic examination of types 2) and 3).
4) Follicular pattern: Characteristic follicles have a thyroidgland-like structure and contain acidophilic material.
Conclusion: Except for the papillary-cystic pattern, the growth pattern is unrelated to the prognosis and behavior of the tumor. However, acinar structure, papillary structure, vacuolated cells and psammoma bodies are important dagnostic features in acinic cell carcinoma.

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Background: Fine-needle aspiration (FNA) of salivary gland tumors is widely accepted as a useful pretreatment diagnostic tool. Many studies have shown that FNA diagnostic accuracy is high. Accurate FNA diagnosis of rare salivary gland tumor types still often remains difficult, however. Histological diagnosis is generally made based on the 2^nd edition of WHO histological typing of salivary gland tumors, which contains many rare tumor categories. Although cytological features of common salivary gland tumors have often been described, few papers have covered rare tumors.
Aim: We selected some rare salivary gland tumor categories-benign tumors: basal cell adenoma, myoepithelioma, and oncocytoma; malgnant tumors: basal cell adenocarcinoma, malignant myoepithelioma, epithelial-myoepithelial carcinoma, salivary duct carcinoma, and undifferentiated carcinoma-having peculiar histological patterns and describe their histological and cytological features.
Conclusion: In FNA cytological diagnostic practice, the existence of such tumors must be recognised even though their incidence is extremely low. Accurate FNA diagnosis, also requires comprehensive knowledge of histological features.

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We report a case of peripheral primitive neuroectodermal tumor of the abdominal cavity in a 24-year old woman. Cytology of ascites consisted of numerous individualy scattered cells and a few small clusters. Tumor cells were small to medium size, with a high nuclear/cytoplasmic ratio. Their nucleoli were prominent. The histology of abdominal tumor in the abdominal cavity showed features similar to cytologic findings. An inmmunohistochemical study showed tumor cells were positive for MIC 2, vimentin, and cytokeratin. We showed the usefulness of immunohistochemistry in the cytology of this rare case.

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