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Anaplastic large cell lymphoma (ALCL) is a non-Hodgkin lymphoma of T-cell or null-cell lineage with variable cytomorphology. We report two rare ALCL cases with carcinomatous and sarcomatous patterns, respectively, in fine needle aspiration (FNA) cytology and histopathology. The first case was a 56-year-old man with enlarged left inguinal lymph node. FNA smears showed a malignant small round cell tumor with nuclear molding. In addition, there were large bi-nucleated and multinucleated cells with wreath-like arrangement of nuclei. ALCL and small cell (neuroendocrine) carcinoma were the possibilities considered. Immunocytochemical studies on FNA smears showed positive reaction for leukocyte common antigen (LCA) and negative results for cytokeratin (CK) and chromogranin. Histopathological examination of the lymph node showed features of ALCL with following immunohistochemical staining results: LCA+, CD30+, CD45RO+, CD20-, CD3+ (weak), and Alk1-. During review of sections, areas resembling a small cell anaplastic carcinoma were observed. The second case was a 24-year-old woman with right cervical lymphadenopathy. FNA smears showed an ALCL with highly atypical large cells including bi-nucleated and donut shaped cells, which were positive for CD30, EMA, and Alk-1 protein, and negative for CD20, CD3, and CK. Histopathological examination corroborated the cytodiagnosis of ALCL, and with positive immunohistochemical staining for CD30, EMA, Alk-1 protein+, BCL6+, and Ki67+ (40% cells) and negative results for CD20, CD10, CD3, CD5, CD15, BCl2, CD79a, and CD68. Sarcomatous components were noticed during review of cytologic and histopathological specimen. Awareness about these unusual cytomorphological patterns in ALCL may be of help in proper diagnosis of this neoplasm.

Anaplastic carcinoma of the pancreas (ACP) is a rare and aggressive variant of pancreatic ductal adenocarcinoma (PDAC). Several studies have attempted to characterize this subtype through case series or single case reports; however, ACP remains underrecognized by cytopathologists in particular, and often lumped under the umbrella of classic PDAC. Here, we review the most up to date data that literature provides about ACP, to bring familiarity with this entity to the cytopathology practice, and to elucidate the role cytopathologists can play in recognizing and diagnosing this subtype on pancreatic aspiration biopsy, before surgical resection. We also describe a rare case of ACP, demonstrating signet ring cell features, that was diagnosed on fine needle aspiration of a pancreatic mass.

Intrathyroidal parathyroid carcinoma is an uncommon malignancy. A 46-year-old male presented with a left neck mass. Computed tomography (CT) scan revealed a hypodense mass in the left thyroid lobe along with evidence of metastatic lymphadenopathy. Aspiration of the left thyroid nodule was performed, and a diagnosis of malignancy was rendered, favoring a primary anaplastic carcinoma. Based on the cytologic diagnosis, the patient underwent a total thyroidectomy. Before the surgery, intact parathyroid hormone (PTH) and calcium level (PTH = 78 pg/mL; Calcium = 10.6 mg/dL) were found to be minimally elevated. On gross examination, a 3.2 cm mass within the left inferior thyroid lobe was seen. Histopathologic examination and ancillary studies supported the diagnosis of a parathyroid carcinoma. We, hereby present, an exceedingly rare presentation of an intrathyroidal parathyroid carcinoma with only minimal elevation of PTH and calcium, mimicking a primary anaplastic thyroid carcinoma on cytologic examination.

Pancreatic anaplastic carcinoma (PAC) is rare and has an aggressive clinical course. We report an autopsy case of PAC focusing on the cytopathological characteristics of the tumor and immunocytochemical staining for vimentin, E-cadherin, and zinc finger E-box binding homeobox 1 (ZEB1), which markers are associated with epithelial markers of epithelial-mesenchymal transition (EMT). A 50-year-old woman presented to our hospital with a chief complaint of jaundice. A pancreatic head tumor and multiple liver nodules were detected on abdominal computed tomography. Biliary cytology under endoscopic retrograde cholangiopancreatography suggested ductal adenocarcinoma. Three months after admission, she died of multiorgan failure. At autopsy, touch imprint cytology using squash preparation of the pancreatic tumor identified two different cell types; numerous isolated malignant cells with large and pleomorphic nuclei and a few clusters showing irregularly overlapped nuclei and irregular contours within the necrotic background. Immunocytochemically, isolated cells were positive for vimentin and ZEB1, and negative for E-cadherin. Conversely, clusters were negative for vimentin and ZEB1, and positive for E-cadherin. Histologically, the tumor was composed of sarcomatous cells with small foci of adenocarcinoma, which were consistent with a diagnosis of PAC. Immunohistochemical staining of the adenocarcinoma and sarcomatous cells corresponded to those of the clusters and isolated malignant cells, respectively. Immunostaining of these EMT markers is useful to distinguish sarcomatous cells from adenocarcinoma and can contribute to the accurate diagnosis of pancreatic tumors with EMT.

Atypical adenoma of the thyroid is a rare form of tumor, and its accurate diagnosis prior to surgical resection is difficult as the histological and pathological morphologies are very similar to those of anaplastic thyroid carcinoma (ATC), and its anaplastic transformation remains to be elucidated. We reported a case of a 75-year-old female with a thyroid isthmus nodule diagnosed repeatedly by FNAC as anaplastic carcinoma. Both the first and second FNAC specimen slides showed a large number of scattered or aggregated atypical cells consisting of large, pleomorphic nuclei with irregular membranes, chromatin clumps and prominent nucleoli. The morphology of the surgical specimen was similar to that of an anaplastic carcinoma and although it showed signs of transition from a normal follicular epithelium, there was no invasive growth or mitosis. This lesion was diagnosed as an atypical adenoma, and a papillary carcinoma was also present in the right lobe of the thyroid. Here we evaluate the molecular features of atypical adenomas in comparison with 9 ATC samples, and discuss whether or not atypical adenomas represent a form of premalignant lesion. Ki-67 expression was found to be very low in atypical adenomas whereas all ATC samples showed high levels of Ki-67 expression. Epithelial-mesenchymal transition (EMT) marker expression suggested that atypical adenomas maintain their epithelial phenotype to a higher degree than do ATCs. Differential diagnosis between ATC and atypical adenoma is difficult by cytological and histological methods alone, and Ki-67 and EMT marker expression may support the diagnosis.

Granulocyte colony-stimulating factor (G-CSF)-producing pancreatic tumors are extremely rare. These tumors have an aggressive clinical course and no established treatment. Here, we report an autopsy case of G-CSF-production in pancreatic anaplastic carcinoma (PAC). A 72-year-old woman presented with a large pancreatic head mass and multiple liver metastases. Laboratory data showed leukocytosis (leukocyte count 113.3 × 103 /µL) and high serum G-CSF levels (441 pg/mL; normal range

Mucinous cystic neoplasms (MCN) of the pancreas can vary from benign to premalignant and malignant. Preoperative diagnosis is essential to offer the patient appropriate treatment. Occasionally these cases may harbor anaplastic carcinoma while clinically masquerade as a pseudocyst. Here in, we report an unusual case of a 37-year old female presented with recurrent abdominal pain that was suspected clinically and by imaging studies to have a pseudocyst. EUS-FNA with internal drainage of the cyst was performed. Cytological evaluation of the cyst fluid showed numerous inflammatory cells composed mainly of many neutrophils admixed with macrophages reminiscent of the usual pseudocyst content but there were scattered rare dyscohesive malignant cells which were highly pleomorphic with multinucleation. Immunostains on the cell block showed immunoreactivity of these cells including the multinucleated cells for Cam 5.2 and AE1/AE3 and focally for Ber-Ep4, Moc -31, and CA19-9. The subsequent resection confirmed the presence of anaplastic (undifferentiated) carcinoma (AC) arising in a MCN of the pancreas. Diagn. Cytopathol. 2016;44:538-542. © 2016 Wiley Periodicals, Inc.

This study was conducted to see the sensitivity, specificity, and accuracy of fine needle aspiration cytology (FNAC) for solitary thyroid nodules and to compare our experience with that of other regions of the world. It was a prospective cross sectional study conducted on 76 thyroid samples submitted and reported at the Department of Pathology, King Edward Medical University, Lahore. There were 65 (85.5%) females and 11 (14.5%) males. Male to female ratio was 1:5.9. Ages of the patients ranged from 10 to 60 year with mean age 35.37 +/- 12.17. Thirty-three (43.42%) samples were indeterminate. There were 30 cases (39.47%) of benign lesions, comprising of colloid goiter, follicular adenoma, and diffuse hyperplasia. The final reports of these cases were almost the same. On FNAC, 13 cases were declared as malignant (6 cases) or suggestive of malignancy (3 cases) or suspicious for malignancy [4 cases (5.26%)]. Only 9 cases (11.84%) were clearly committed as malignant lesions, comprising of papillary carcinoma, anaplastic carcinoma and suggestive of follicular carcinoma. Comparison of malignant cases on histopathology (14 cases) was close to that of FNAC (13 cases). After comparison of FNAC results with histopathology, overall sensitivity of FNAC was found to be 90%, specificity 87.5%, and accuracy 87%, while positive predictive value (PPV) was 93% and negative predictive value (NPV) was 79.5%. In conclusion, we recommend this procedure in the light of views of other experts as a primary investigation of thyroid lesions. We strongly recommend the suggestion that in a patient with one or more thyroid nodule, FNAC should be advised for every patient for exclusion of cancer. We will also encourage the clinicians to embrace this procedure in the initial management of patients. As FNAC is inexpensive, sensitive, specific, and an accurate procedure it should be adapted as an initial investigation of thyroid diseases in all tertiary hospitals in developing countries like Pakistan.

Cultured anaplastic cell lines with previously characterized phenotypes are considered to be the best positive controls for immunocytochemistry. We assessed the validity of using anaplastic cell line cytospins as positive controls for immunocytochemistry performed on ThinPrep®-processed clinical samples. We compared ThinPrep®-processed slides and air-dried cytospins from cultured anaplastic cell lines for intensity and pattern of staining. Also, antigen preservation was assessed over a 3-mo period, using a panel of 16 primary antibodies and 12 anaplastic cell lines. A three-step alkaline phosphatase procedure was used except when in a single instance the EnVision™ method was employed. If appropriately stored, both preparations showed excellent correlation with no decrease in antigenicity during the 3-mo testing period. ThinPrep®-processed slides from clinical samples are ideal for immunocytochemistry, because internal negative controls can be performed for each test. We recommend the use of cytospins for positive controls because of the lower cost. Diagn. Cytopathol. 25:303–308, 2001. © 2001 Wiley-Liss, Inc.

Four pure insular carcinomas (IC) and one IC with focal anaplastic carcinoma (AC) of the thyroid with cytologic evaluation by fine-needle aspiration (FNA) were reviewed. The needle aspirates from the four pure ICs revealed abundant monomorphic follicular cells present singly, in small, loose aggregates, and in cohesive trabecular and acinar clusters. Tumor cells showed fragile, ill-defined, granular cytoplasm and oval nuclei with conspicuous or inconspicuous nucleoli. The case of IC with focal AC yielded, in addition to the follicular cells as seen in the FNA of the 4 cases of pure IC, large pleomorphic malignant cells with prominent nucleoli that were characteristic for an AC, giant-cell type. No intact insulae of tumor cells were identified in any of the 5 cases. Thus, a thyroid IC may be suspected if abundant cohesive and dyshesive monomorphic follicular cells are present in the tumor FNA. However, a firm diagnosis of thyroid IC can only be made by histologic examination of the excised tumor.

Cell cannibalism is defined as the ability of a cell to phagocytose another cell. Malignant tumor cells may develop phagocytic property and demonstrate phagocytosis of own cells or cells of other series like neutrophils and lymphocytes. We report 11 cases in which the tumor cells showed evidence of neutrophil phagocytosis/emperipolesis on FNAC smears. Cases of malignancies diagnosed on FNA over a period of 1 year were retrieved, and smears were examined for neutrophil phagocytosis by tumor cells. These cases were classified according to type and differentiation of malignancy. The cytomorphological features and background inflammation were also studied at both primary and metastatic site. Of 362 malignant cases diagnosed on FNA smears, in 11 cases (3.09%), tumor cells showed neutrophil phagocytosis. The background showed increase in polymorphs in all cases. All the cases were associated with metastasis at presentation and were high-grade tumors cytologically. There were three cases of anaplastic carcinoma, two cases of adenocarcinoma, two cases of carcinoma breast, two cases of anaplastic non-Hodgkins lymphoma, one case each of squamous cell carcinoma and small cell carcinoma from larynx and lung, respectively. Phagocytic activity by tumor cells is uncommon and usually seen in high-grade/poorly differentiated malignancies. It is frequently associated with metastatic disease. On cytology smears, true phagocytosis of neutrophils by tumor cells has to be distinguished from superimposed inflammatory cells from the background. The tumor cells also need to be distinguished from histiocytes displaying phagocytosis.

Transformation of a differentiated thyroid carcinoma is an infrequent occurrence and is usually associated with a dismal prognosis. Following a long-standing history of papillary carcinoma of the thyroid, the patient in the present report developed anaplastic thyroid carcinoma. The anaplastic component initially arose in the setting of papillary carcinoma with tall-cell features, represented a very small proportion of the tumor, and was overlooked at the time of the original diagnosis. Several years later, the patient developed a recurrent neck mass. Fine-needle aspiration (FNA) of this mass revealed a population of atypical spindle cells arranged singly and in papillary clusters which lacked the classical cytologic features of papillary carcinoma of the thyroid. Histology of the resected mass revealed an unusual and recently described subtype of thyroid carcinoma, termed "anaplastic spindle-cell squamous carcinoma," which has been reported as occurring in association with tall-cell papillary carcinoma. The FNA findings of this unusual subtype of anaplastic thyroid carcinoma are presented. Diagn. Cytopathol. 1999;21:413-418.

A disparate group of salivary gland neoplasms is characterized by small, uniform, hyperchromatic, basaloid cells. This “small blue cell” pattern is most common in non-Warthin's types of monomorphic adenoma, or in adenoid cystic carcinoma. Small cell anaplastic carcinoma (primary or metastatic), metastatic basaloid squamous cell carcinoma, basal cell adenocarcinoma, and metastatic nasopharyngeal carcinoma are rarely encountered but may present a cytologically similar appearance. We report one female and two male patients (median age = 84 yr) with cutaneous-type basal cell carcinoma (BCC) aspirated from metastatic deposits in the parotid (2 cases) or the submandibular (1 case) gland. One was correctly classified at the time of aspiration, based on a previous history of multiple facial BCC. One was interpreted as carcinoma, the previous history being unavailable at the time of FNA. Smears in these two cases show necrosis and rare keratotic cells. The third case was mistaken for pleomorphic adenoma (PA); the smears showed metachromatic fragments of collagenous tumor stroma that were misinterpreted as the matrix material typical of PA. Similar material was identified in the other two cases. When the “small blue cell” pattern is encountered in salivary gland cytology, one should consider BCC, especially if necrosis is identified. The desmoplastic tumor stroma of BCC may mimic the chondroid matrix of PA. Careful consideration of previous history is very important. Diagn. Cytopathol. 16:247–252, 1997. © 1997 Wiley-Liss, Inc.

Malignant pleural effusions due to prostatic carcinoma are rare. We examined the cytologic and clinical presentations of 14 malignant pleural effusions caused by prostate cancer. These cases represented 2.3% of all positive pleural effusions at our institution. All patients (n = 10) had high grade, high stage tumors, including three with small cell anaplastic carcinoma. Three cases had clinically documented metastases to pleura, and in two cases, metastases were documented at autopsy. Most tumor cells had large nucleoli and were arranged in small, loosely cohesive groups. Fluids due to the small cell type of prostate carcinoma often contained a mixture of cells similar to those seen in small cell carcinoma of other sites such as the lung, as well as cells resembling the more typical type of prostate cancer. Prostatic specific antigen and prostatic acid phosphatase were positive in less than 50% of these malignant effusions. We conclude that prostatic carcinoma in pleural effusions occurs most commonly in high grade, high stage tumors and has a characteristic cytologic appearance. Negative staining for PSA and PAP does not rule out a prostatic source for malignant cells in effusions.

Four cases of non-Hodgkin lymphoma of thyroid, diagnosed by fine-needle aspiration (FNA) cytology during a period of 3 1/2 yr constituted 0.2% of 1,716 thyroid FNAs and 3.4% of 118 thyroid neoplasms. The age of the patients ranged from 42 to 78 yr with an average of 63 yr and all were females. Three cases had thyroid swellings, and one case had cervical lymphadenopathy and fullness in the thyroid region. The lymphomas were categorized as mixed small and large cell lymphomas, large cell lymphoma, small noncleaved lymphoma (non-Burkitt-type), and plasmacytoid lymphoma. Histopathology as well as immunohistochemistry confirmed the cytodiagnosis of lymphoma in the first and fourth cases. In the second case where possibility of anaplastic carcinoma could not be ruled out altogether at initial cytologic examination, the histopathology report was undifferentiated carcinoma but immunohistochemically it was proved to be a B-cell neoplasm.

One hundred thirty-two cases diagnosed as non-Hodgkin's lymphoma (NHL) by fine-needle aspiration cytology (FNAC) and histology, and 43 cases in which there were minor or major discrepancies between cytology and histology for diagnosis of NHL, were reviewed. The diagnostic accuracy of FNAC for NHL was 86.3% at the initial diagnosis. Following review, all the 132 cases initially diagnosed as NHL by cytology and histology remained so with minor changes in subtypes in a few cases. Of the 43 discrepant cases, 28 turned out to be NHL and 6 as Hodgkin's disease (HD); 3 were anaplastic carcinoma; and in 6 cases the discrepancy still persisted. Diagnostic accuracy of FNA for NHL improved to 98.0% following review. Categorization of histologically diagnosed NHL cases under working formulation showed that 10.4%, 21.5%, and 57.7%, respectively, were low, intermediate, and high-grade lymphomas. The corresponding figures were 16.6%, 18.4%, and 60.1%, respectively, in cytology. The diagnostic accuracy of cytology for subtyping was found to be 67.5%.

A case of coexistent papillary and anaplastic carcinoma of the thyroid is presented. The diagnosis of papillary carcinoma was made by fine-needle aspiration biopsy (FNAB); however, it did not correspond to the aggressive clinical behavior of the tumor. Subsequent biopsies revealed anaplastic carcinoma in the thyroid and pretracheal tissue. This case most likely represents anaplastic transformation in a pre-existing papillary carcinoma. The limitations of diagnosing this entity by FNAB as well as some possible solutions are discussed.

Four cases of anaplastic carcinoma of the thyroid were diagnosed in 1,519 thyroid aspirates. All patients had unilateral or diffuse nodular enlargement of the thyroid. One patient had a concurrent grade 1 mucinous carcinoma of the ovary. Cytologically, the neoplasms were characterized by pleomorphic giant or spindle cells with multilobulated, single or multiple nuclei. The chromatin pattern was clumped with prominent parachromatin clearing, and there were multiple prominent nucleoli. Associated papillary and follicular structures were recognized in two aspirates. All cytologic preparations were considered diagnostic of malignancy. Examination of histologic material revealed the same elements identified cytologically on the aspiration smears. Three patients died shortly after diagnosis due to massive local tumor growth in the neck. One patient, who received radiation therapy, had a prolonged survival of 30 mo, but died then of local neck recurrence. The cytologic features of anaplastic carcinoma parallel their histologic appearance. Histologic confirmation of cytologically diagnosed anaplastic carcinoma is not necessary.

Chordomas are rare neoplasms of notochord derivation that arise along the craniospinal axis. Their incidence along the cervical spine and close proximity to the thyroid can pose diagnostic pitfalls. We report a case of a paraspinal mass juxtaposed adjacent to the thyroid with intranuclear inclusions of papillary carcinoma, abundant eosinophilic cytoplasm of an oncocytic lesion, and pleomorphism of anaplastic carcinoma that expressed thyroglobulin and emulated a malignant thyroid neoplasm. However, subsequent histological examination revealed a chordoma with perithyroidal soft-tissue invasion. This case highlights the significance of including chordoma in the differential diagnosis of a thyroid neoplasm and interpreting thyroglobulin reactivity warily, because its inadvertent tracking during fine-needle aspirates (FNAs) can produce false positive staining of nonthyroidal cells.

Anaplastic carcinoma of the thyroid is known for its highly aggressive behaviour and rapid spread. While the giant cell variant is a well recognized morphologic pattern, the presence of osteoclast-like giant cells is a rare occurrance. We report a case of anaplastic carcinoma of the thyroid with focal presence of osteoclast-like giant cells occurring in an elderly male patient, diagnosed on aspiration cytology. Diagn. Cytopathol. 2007;35:111–112. © 2007 Wiley-Liss, Inc.

Recently, the demonstration of DAP IV activity in thyroid cells aspirates has been proposed as an useful tool for the diagnosis of malignancy. We have studied the enzymatic activity of DAP IV, using the modified method of Lodja, in a series of 336 selected aspirates of the thyroid gland with the following cytologic diagnosis : 236 nodular hyperplasias, 60 follicular proliferations, eight Hashimoto's thyroiditis, eight Hurthle-cell proliferations, 20 papillary carcinomas, two anaplastic carcinomas, and two medullary carcinomas. The results were subjectively evaluated on the basis of staining intensity and extension in a minimum of 200 cells. Strong-to-moderate enzymatic activity with an extension of more than 40% of the cells were exclusively seen in follicular-cell derived carcinomas (papillary carcinoma, Hurthle-cell carcinoma, and follicular carcinoma). Medullary carcinoma, anaplastic carcinoma, and benign conditions were negative or weakly stained. Cytohistologic correlation in 88 patients operated on showed the following results : 26 nodular hyperplasia (18 nodular hyperplasia and eight follicular adenomas ), 36 follicular proliferation (24 nodular hyperplasia, six, adenomas, three papillary carcinomas, three follicular carcinomas), two Hurthle-cell proliferation (one Hurthle-cell adenoma and one Hurthle-cell carcinoma), ), 20 papillary carcinomas, two medullary carcinomas, and two anaplastic carcinomas. DAP IV staining was moderate to strong and extensive in all malignant tumors initially diagnosed as follicular or Hurthle-cell proliferations. We conclude that DAP IV activity is present in malignant differentiated thyroid tumors of follicular cells (papillary carcinoma, follicular carcinoma, Hurthle-cell carcinoma), but it is identified neither in medullary carcinoma nor in anaplastic carcinoma. Therefore, its usefulness is restricted to the diagnosis of follicular cell malignancies.

Anaplastic carcinoma of the thyroid (ACT) is a rare subtype of thyroid neoplasm. This tumor represents approximately 5–10% of all thyroid malignancies and its poor prognosis has not changed in 25 years. ACT often arises in a long-standing thyroid nodule and has been documented to be associated with a variety of more well-differentiated thyroid carcinomas. We describe the cytologic features of a case in which the patient had a 10-yr history of a thyroid nodule. The ACT in this case had a cytologic and histologic appearance of several different subtypes of thyroid carcinomas. Diagn Cytopathol 1994;11:60–63. © 1994 Wiley-Liss, Inc.

A case of small-cell anaplastic carcinoma of the prostate, occurring in an 82-year-old man with prior prostatic adenocarcinoma, is reported. The exfoliated tumor cells in the urine were seen singly or in loose aggregates with molding. They showed scant cytoplasm and slightly pleomorphic, hyperchromatic nuclei with inconspicuous nucleoli. By electron microscopy the tumor consisted of primitive epithelial cells without glandular or neuroendocrine differentiation. The tumor pursued a highly aggressive course, and the patient died of metastatic disease 4 mo after the diagnosis.

This article reports on a series of 432 patients with positive respiratory (sputum and bronchial) cytology and proven malignant respiratory tract disease as corroborated by detailed verification criteria; 54 of these patients were diagnosed as having small-cell anaplastic carcinoma (SCAC). None of the 31 patients with autopsy-and/or biopsy-proven disease had false-positive results for SCAC. Typing accuracy for SCAC versus non-SCAC was 97.7% in the 263 patients with histologic confirmation of their respiratory tract disease. Twenty-three of the 54 patients (42.6%) were treated for SCAC solely on the basis of positive cytology in the context of compatible clinical data. This finding underscores the great importance of proper specimen preparation, quality control procedures, and diligent clinical follow-up in an era of heightened cost-containment awareness when many patients with pulmonary SCAC will be treated on the basis of positive cytology not immediately confirmed by histologic methods. Diagn Cytopathol 1988;4:202–205.

A case of primary pineal germinoma with widespread extracranial metastasis in a 36-year-old man is presented. A clinical work-up revealed bilateral pleural effusions, ascites, and metastatic lesions involving the lung. Cytology and electron microscopic study of the pleural and ascitic fluid and of the fine needle aspiration material revealed metastatic germinoma. Although the cytologic features were not distinct from those of anaplastic carcinoma, they were distinguishable from those of glial neoplasms, lymphoma, and sarcoma. The computed tomography findings, elevated human chorionic gonadotropin level, and electron microscopic features contributed significantly to the diagnosis of extracranial metastasis of the pineal germinoma. Metastatic spread most likely occurred via the ventriculoperitoneal shunt.

Our experience with fine-needle aspiration cytology in five cases of malignant lymphoma of the thyroid is reported. Only one case was correctly diagnosed as malignant lymphoma from the original cytologic reports. Three cases were misdiagnosed as anaplastic carcinoma of small-cell type and two of these three cases were subsequently revised as malignant lymphoma after a second aspiration. The final case was misdiagnosed as chronic thyroiditis at both the first and second aspirations; following a third aspiration, 8 mo later, it was correctly diagnosed as malignant lymphoma. Cytological findings of malignant lymphoma are as follows: many malignant cells are distributed as isolated cells and show monotonous features. Malignant cells are slightly larger than normal lymphocytes. Sometimes cleaved cells or large nucleoli are visible. The differential diagnosis of cytologic findings of malignant lymphoma and the other thyroid diseases is discussed in detail.