Can cytology and the Thyroid Imaging, Reporting, and Data System (TI-RADS) identify noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) before surgery?

INTRODUCTION

In 2017, the American College of Radiology (ACR) created the Thyroid Imaging, Reporting, and Data System (TI-RADS) to select thyroid nodules for fine-needle aspiration (FNA). The objective of this study is to find out whether ACR TI-RADS is useful in triaging thyroid follicular cells with papillary-like nuclear features obtained by FNA to determine the extent of surgery.

MATERIAL AND METHODS

The grayscale ultrasound of 76 noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), 41 encapsulated (E), and 79 infiltrative (I) follicular variant (FV) of papillary thyroid carcinoma (PTC) were reviewed and assigned TI-RADS points and then suspicion levels.

RESULTS

Of the 39 tumors with high suspicion level, 32 were IFVPTC, and seven were EFVPTC. Of the 137 tumors with moderate suspicion level, 47 were IFVPTC, 34 were EFVPTC, and 56 were NIFTP. Of the 19 tumors with mild suspicion level, all were NIFTP. The only tumor with no suspicion was an NIFTP. IFVPTC had a significantly higher suspicion level than EFVPTC and NIFTP (P < 0.0001). The difference in suspicion level between EFVPTC and NIFTP is not statistically significant. None of the cases of NIFTP in the study had a high suspicion level.

CONCLUSIONS

The study demonstrates that cytology interpreted in the context of ACR TI-RADS suspicion levels can separate NIFTP from many IFVPTC and a few EFVPTC with overt invasion. PTC could be diagnosed in cytology if cells with papillary-like nuclear features derived from TR5 nodules. The nodules with TR4 or less that yield similar cells require surgical pathology to diagnose FVPTC with microscopic capsular or vascular invasions.

Pathologic basis of the sonographic differences between thyroid cancer and noninvasive follicular thyroid neoplasm with papillary-like nuclear features

Ultrasonography is pivotal in triage thyroid biopsy in the era after the identification of noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP). This pictorial essay illustrates the pathologic basis of the sonographic features that distinguish NIFTP from thyroid cancers. In this study, we present the correlations of ultrasonography to ×1 histopathology to assess shape and margin characteristics. Markedly hypoechoic nodules correlate to microfollicular/solid nodules, while isoechoic/hyperechoic thyroid nodules correlate to normofollicular/macrofollicular nodules. The ultrasound findings of NIFTP and minimally invasive encapsulated thyroid cancers are similar. Both are well-circumscribed, oval-to-round nodules with regular margins. Blurred or microlobulated margins indicate infiltrating tumors, while lobulated margins are characteristic of expansile tumors. Overtly invasive encapsulated tumors are characterized by oval-to-round nodules with irregular or lobulated margins. The ultrasound findings for infiltrative thyroid cancers show at least one of the following malignant features: marked hypoechoicity, taller-than-wide shape, microcalcifications, and blurred or microlobulated margins.

Most Thyroid Cancers Detected by Sonography Lack Intranodular Vascularity on Color Doppler Imaging: Review of the Literature and Sonographic-Pathologic Correlations for 698 Thyroid Neoplasms

OBJECTIVES

This study investigated the controversy of whether hypervascularity on color Doppler sonography correlates with thyroid malignancy by reviewing the literature and sonographic-pathologic correlation.

METHODS

Over a 20-year period, 698 thyroid nodules had color Doppler and histopathologic data. Intranodular vascularity was graded 0 to 3+, and histopathologic findings were recorded.

RESULTS

The data were collected from 698 patients (557 women and 141 men) with a mean age of 48 years (range, 16-87 years). Of the 698 neoplasms, 425 were malignant (mean size, 1.7 cm; range, 0.4-9 cm; 150 ≤1 cm), and 273 were benign. The carcinomas included 391 papillary, 12 Hürthle cell, 9 medullary, 6 follicular, 5 poorly differentiated, and 2 anaplastic. The grading of intranodular vascularity was 0 in 63.3%, 1+ in 12.9%, 2+ in 6.6%, and 3+ in 17.4%. Among thyroid carcinomas, follicular carcinoma and the encapsulated subtype of the follicular variant of papillary carcinoma had significantly higher intranodular vascularity than the rest (P < .0001). Benign neoplasms included 226 follicular adenoma/adenomatoid nodules (mean size, 3.2 cm; range, 1.2-8.0 cm), 42 Hürthle cell adenoma/adenomatoid nodules (mean size, 2.6 cm; range, 0.8-5.5 cm), and 5 hyalinizing trabecular adenomas (mean size, 2.4 cm; range, 0.6-6.0 cm; 4 ≤1 cm). The grading of intranodular vascularity was 0 in 6.9%, 1+ in 12.1%, 2+ in 2.6%, and 3+ in 78.4%. Intranodular hypervascularity was associated with adenoma/adenomatoid thyroid nodules, whereas a lack of vascularity was related to thyroid carcinomas (P < .0001).

CONCLUSIONS

Most sonographically detected thyroid cancers lack intranodular vascularity, and most hypervascular thyroid nodules are adenoma/adenomatoid nodules, the encapsulated subtype of the follicular variant of papillary carcinoma, or follicular carcinomas.

Cytohistology of papillary carcinoid and emerging concept of pulmonary neuroendocrine neoplasms

This timely review starts by reporting the clinical, cytologic and histologic features of a morphologic variant of pulmonary carcinoid tumor forming exclusively of papillae. This growth pattern is so rare that it was not included in 2014 WHO classification of pulmonary neuroendocrine neoplasms. The current concept is reviewed, and example of spindle cell carcinoid, atypical carcinoid, large cell neuroendocrine carcinoma, and small cell carcinoma are illustrated with fine needle aspiration cytology, surgical and clinical follow-up. Finally, the new findings in cell biology and molecular biology that led to the emerging concept that carcinoids and high-grade neuroendocrine lung carcinomas are separate biological entities are reviewed and summarized in a tumorigenic module.

Fine-needle aspiration cytology of the solid variant of papillary thyroid carcinoma: a study of 13 cases with clinical, histologic, and ultrasound correlations

BACKGROUND

The solid variant of papillary thyroid carcinoma (SVPTC) comprises approximately 3% of thyroid cancers, and there are conflicting reports about its behavior in the literature. The cytology of SVPTC is limited to 3 single case reports, a review article, and a monograph. We present the first cytologic study of SVPTC.

METHODS

Fine-needle aspiration smears obtained with ultrasound guidance from 13 patients with histologically pure SVPTC were reviewed, and the cytologic features recorded. Ultrasound images were retrieved from radiology and were correlated with low-power histology images. Intratumor vascularity on Doppler imaging was correlated with cellularity in cytology samples.

RESULTS

Three cytomorphologic patterns of SVPTC were identified: cohesive, syncytial-type tissue fragments; microfollicles/trabeculae; and dyshesive single cells. All 3 SVPTCs in the first group were encapsulated without invasion. Two of 6 SVPTCs in the second group had a single lymph node metastasis; 4 were encapsulated, and 2 had pushing borders. Ultrasound images in the first and second SVPTC groups were similar, with the majority revealing a well defined, solid nodule with minimal intranodular vascularity. All 4 SVPTCs in the third group had infiltrative borders; and, with the exception of one 0.8-cm tumor, all had multiple lymph node metastases. Ultrasound in the third group revealed irregular borders. RET/PTC1 and RET/PTC3 mutations were found in 2 cases of the third group.

CONCLUSIONS

SVPTCs are heterogeneous tumors. The cohesive, syncytial tissue-fragment pattern can be recognized as SVPTC in smears and is associated with encapsulation and indolent behavior. The microfollicular/trabecular pattern is indistinguishable from that of the follicular variant of papillary thyroid carcinoma and has intermediate behavior. The dyshesive single-cell pattern correlates with infiltrative tumor growth and may not be unique to SVPTC.

Encapsulated follicular variant of papillary thyroid carcinoma: fine-needle aspiration with ultrasound and histologic correlation of 41 cases

OBJECTIVE

The encapsulated follicular variant of papillary carcinoma (FVPC) was recently reported to have genetic alterations and biological behavior closer to follicular adenoma/carcinoma than classic papillary carcinoma and unencapsulated FVPC. The objective of this study is to alert cytologists to this new subtype and to report our experience.

STUDY DESIGN

Cytology of 41 cases of surgery-proven encapsulated FVPC was reviewed and correlated with histopathology and ultrasound findings. These cases were collected over 19 years from 188 aspirates reported as 'suspicious or atypical, cannot exclude FVPC' and from 245 aspirates reported as follicular neoplasm.

RESULTS

Thirteen aspirates had diffusely atypical nuclei, 20 aspirates had mixed normal and atypical nuclei, and 8 aspirates had no atypical nuclei. On histology, papillary nuclei were distributed focally in the second and third groups. Crowded, oval, clear nuclei occurred in nearly 80% of the cases, nuclear grooves occurred in 12.2%, and nuclear pseudoinclusions occurred in 4.9%. Capsular invasion without angioinvasion was present in 30% of encapsulated FVPCs, with angioinvasion in 17.5% and lymph node metastasis in 7.5%. Most encapsulated FVPCs were benign-appearing on ultrasound with round-to-oval, circumscribed nodules with a hypoechoic rim.

CONCLUSIONS

Encapsulated FVPC is more difficult to recognize on fine-needle aspiration and ultrasound than unencapsulated FVPC.

Cribriform morular variant of papillary thyroid carcinoma: clinical and cytomorphological features on fine-needle aspiration

BACKGROUND

Cribriform-morular variant of papillary thyroid carcinoma (CMV-PTC) is a rare tumor that may arise in patients with familial adenomatous polyposis (FAP), although sporadic instances of this tumor have been reported. When it arises in FAP, CMV-PTC may present before colonic manifestations are apparent, so proper identification and classification are essential for prompt assessment of the colonic disease status and genetic and familial counseling.

METHODS

Nine cases of PTC with cribriform morular cytomorphology were identified at 2 large tertiary-care hospitals; 6 were true CMV-PTC with positive β-catenin and 3 were CMV-like PTC with negative β-catenin. A review of the cytomorphology and a cytology-histology correlation were performed.

RESULTS

Only 1 patient presented with a known history of FAP. Patients presented with a median age of 41 years (range 19-64 years). There was a clear female predilection; 8 of 9 patients (89%) were female. All cases demonstrated the classical nuclear and architectural features of PTC. In addition, the most salient features were large tissue fragments with cribriform architecture and dense cellular morules. The elongated cellular shape of the tumor cells led to the misclassification of one tumor as a tall-cell variant of PTC on the FNA material.

CONCLUSION

CMV-PTC or CMV-like PTC demonstrate cytomorphological features that overlap with classic PTC. β-Catenin immunostaining plays an important role in making a definitive diagnosis.

Cytological features of clear cell thyroid tumors, including a papillary thyroid carcinoma with prominent hobnail features

Primary thyroid tumors with extensive clear cell changes are extremely rare. More than 10,000 ultrasound-guided thyroid fine needle aspirations examined over a period of 17 years by the first author, only one of the 530 (<0.2%) papillary thyroid carcinomas (PTCs) and three of the 42 (7.1%) follicular thyroid carcinomas (FTCs) had extensive cytoplasmic clearing. Thyroidectomies were performed for these cases at four different hospitals in New York City. Final pathology was available for review in each of the four cases. Histology showed a 1.5-cm PTC with prominent hobnail features and clear cell change in a 31-year-old woman, a 4.3-cm FTC without angioinvasion in a 31-year-old woman, a 4.5-cm angioinvasive FTC in a 45-year-old man, and a 2-cm FTC with extensive angioinvasion in a 41-year-old woman with McCune-Albright syndrome (previously published). On ultrasound, the FTCs were solid circumscribed nodules and the PTC had an irregular margin. In these cases, the etiology for the cytoplasmic clearing included accumulation of glycogen in the PTC, accumulation of vesicles in two of the FTCs, and accumulation of lipid droplets in a FTC with extensive angioinvasion. Review of the cytologic literature showed 17 cases of follicular-derived thyroid tumors with extensive clear cell change. To the best of our knowledge, this is the first cytologic report of PTC with hobnail features and extensive clear cell change.

Can abundant colloid exclude oncocytic (Hürthle cell) carcinoma in thyroid fine needle aspiration? Cytohistological correlation of 127 oncocytic (Hürthle cell) lesions

OBJECTIVE

The objective of the present study was to find out whether the presence or absence of certain cytological features can exclude oncocytic (Hürthle cell) carcinoma in thyroid fine needle aspiration (FNA) to minimize unnecessary surgery.

METHODS

Over a 17-year period, 127 hypercellular, oncocyte-exclusive, lymphocyte-absent aspirates obtained via ultrasound-guided FNA with on-site assessment had histology slides for review. The presence or absence of six cytological features (microfollicular arrangement, discohesive single cells, small cell dysplasia, large cell dysplasia, transgressing blood vessels and colloid) and one histological feature (macrofollicular component) were determined for each case independently by two cytopathologists.

RESULTS

Histology showed 12 (9.4%) cases of Hashimoto thyroiditis, 23 (18.1%) oncocytic adenomatoid nodules in nodular goitre, 66 (52.0%) oncocytic adenomas and 26 (20.5%) oncocytic carcinomas (13 minimally invasive without angioinvasion, six minimally invasive with angioinvasion, seven widely invasive). Histologically, a macrofollicular component was present in seven of 26 (26.9%) oncocytic carcinomas, including one case with abundant thin colloid. A microfollicular arrangement, discohesive single cells, small cell dysplasia, large cell dysplasia and transgressing vessels were present in oncocytic carcinoma, oncocytic adenoma and oncocytic adenomatoid nodules in nodular goitre.

CONCLUSIONS

A macrofollicular component is frequently present in oncocytic carcinoma, oncocytic adenoma and oncocytic adenomatoid nodules in nodular goitre. None of the cytological features studied, including abundant colloid, can exclude oncocytic carcinoma. Oncocytic carcinoma can only be excluded by thorough histological examination of thyroidectomy specimens. A molecular marker is needed to triage oncocytic lesions in thyroid FNA.

Fine-needle aspiration of mucin-producing thyroid tumors

OBJECTIVE

Mucin-producing thyroid tumors are extremely rare. Nonetheless, we have encountered three such cases in fine-needle aspiration. We report the cytologic and histologic findings and review the literature.

STUDY DESIGN

Cytologic features were studied on direct smears using Romanovsky stain to detect background substance and Papanicolaou stain to analyze nuclear and cytoplasmic features. The cytologic features were correlated with histology. Mucin was demonstrated by mucicarmine, Alcian Blue/PAS, and Alcian Blue (pH 2.5).

RESULTS

The cytologic features related to mucin include: (1) thick luminal mucin globules and signet ring cells aspirated from an 83-year-old woman with a 3-cm signet ring cell follicular adenoma, (2) abundant fluffy mucin containing signet ring cells in cohesive fragments aspirated from a 75-year-old man with the bilateral signet ring cell follicular variant of papillary carcinoma, which is the first case in the English literature, and (3) abundant thin mucoid mucin aspirated from the lymph node of an 86-year-old woman with a 5-cm mucinous poorly differentiated thyroid carcinoma.

CONCLUSION

The occurrence of mucin in thyroid fine-needle aspiration does not necessarily indicate metastasis, and the presence of mucin in cervical lymph nodes does not exclude the thyroid gland as a possible primary.

Large cell carcinoma of the lacrimal gland diagnosed by fine needle aspiration biopsy

A 67-year-old man presented with a 6-month history of a malignant appearing left lacrimal gland mass. Fine needle aspiration biopsy was performed in the office, diagnosing the mass as large cell carcinoma (LCCA) of the lacrimal gland. This represents the second reported case of LCCA of the lacrimal gland and details the potential for FNA biopsy to successfully yield the diagnosis. LCCA of the lacrimal gland is rare, but should be considered in cases of malignant lacrimal gland neoplasms.

Cystic papillary thyroid carcinoma in fine needle aspiration may represent a subset of the encapsulated variant in WHO classification

This study audits the reliability of ultrasound-guided fine needle aspiration (FNA) in excluding papillary thyroid carcinoma (PTC) in thyroid cysts containing mural nodules, and investigates the histological counterpart of cystic PTC diagnosed on FNA. Using a 10-5 MHz ultrasound probe and a 27-gauge needle, solid portions of thyroid nodules were sampled and assessed immediately using both Diff-Quik and Ultrafast Papanicolaou stains. Unlike usual PTCs that demonstrate hypercellularity, the aspirates of cystic PTC showed low cellularity and consisted of papillae with atypical nuclei scattered in abundant thin colloid. Over a period of 13 years, histological follow-up was obtained from 11 women and 6 men in whom cystic PTC was reported on FNA. This represented 4.4% of 383 cases of PTC reported and 0.25% of all thyroid FNAs performed. In all 17 cases, histopathology showed encapsulated PTC in various stages of cystic degeneration. Sonography correlated well with histopathology, where findings ranged from cysts with small mural nodules to solid nodules with pockets of thin colloid. In 87 patients with thyroid cysts containing mural nodules, FNA findings were benign, as was clinical follow-up that ranged from 1 to 12 years. In conclusion, ultrasound-guided FNA, if performed in the manner described, can reliably distinguish cystic PTC from a benign cyst with a mural nodule. Cystic PTC on FNA in this series correlates to a subset of the encapsulated variant of PTC, an entity described in the 1988 WHO Histological Typing of Thyroid Tumours in the good prognostic category.

Adenomatoid nodules are the main cause for discrepant histology in 234 thyroid fine-needle aspirates reported as follicular neoplasm

According to several large studies, the surgical pathologist renders a non-neoplastic diagnosis in ∼20-40% of thyroid fine-needle aspiration (FNA) cases reported as follicular neoplasm. This study analyzes the cause of this poor correlation between cytology and histology. Cases consisting of oncocytic (Hurthle) cells were excluded from study. During the study period from January 1996 to April 2010, histologic follow-up was available for 234 of 670 cases (34.9%) reported as follicular neoplasm on ultrasound-guided thyroid FNA. Sonographic and Doppler data were available in all cases and included nodule location, size, echogenicity, and vascularity. Of the 234 aspirates with follow-up, surgical pathology reported 130 cases (55.6%) of follicular adenoma, 15 cases (6.4%) of follicular carcinoma, 14 cases (6.1%) of follicular variant of papillary carcinoma, and 75 cases (32.3%) of nodular goiter. Recuts of those index nodules reported as nodular goiter were examined independently by two pathologists using the 2× objective lens. Adenomatoid nodule was defined as an insufficiently encapsulated "blue" nodule of increased nuclear density when compared with the surrounding thyroid. Of the 75 cases reported as nodular goiter, 60 index nodules (80%) fulfilled the described criteria for adenomatoid nodule, while 15 did not. In conclusion, adenomatoid nodules are the main cause of poor histologic correlation with follicular neoplasm reported by FNA. If "increased nuclear density at scanning magnification" were adopted by surgical pathologists as the major diagnostic criterion for follicular adenoma rather than encapsulation, noncorrelated cases would be reduced from 32 to 6.4%.

Histiocytic sarcoma with interdigitating dendritic cell differentiation: a case report with fine needle aspiration cytology and review of literature

A hybrid histiocytic sarcoma-interdigitating dendritic cell sarcoma was found in a small perinephric lymph node of an asymptomatic 80-year-old man, who presented a year ago with two small foci of lung metastasis found during routine chest X-ray. Fine needle aspiration cytology demonstrated interconnecting long and thin cell processes radiating from dendrite-like neoplastic cells with oval, enlongated, reniform, and irregular nuclei with vesicular chromatin and distinct nucleoli. Histology showed spindled epitheliod and histiocytic cells with abundant, slightly eosinophilic cytoplasm with indistinct cell borders and forming fascicles in a vague storiform pattern with interspersed T-lymphocytes. Immunohistochemically, the neoplastic cells were strongly positive for histiocytic markers: CD163, CD68, lysozyme, and PU.1, as well as strongly positive for dendritic cell markers: S100 and fascin, but were negative for CD1a (Langerhans cell marker), CD21/CD35 (follicular dendritic cell markers), B-cell, and T cell markers. This case is compared to the four hybrid histiocytic-dendritic sarcomas reported since 1983.

Multifocal granular cell tumor presenting as an esophageal stricture

INTRODUCTION

Granular cell tumors are uncommonly found in the gastrointestinal tract with slow progression and are usually benign though they may have propensity for malignant transformation. Initially attributed to neuronal origin through immunohistochemistry, there has been controversy with increasing reports of granular cell tumors of non-neural origin.

CASE REPORT

We report a case of multifocal granular cell tumor involving the esophagus and stomach in a young female with history of dysphagia for 9 years with worsening symptoms. She had been managed at another facility with repeated dilations for presumed benign peptic stricture. Radial endosonography (EUS) of the proximal end of stricture showed a posterior submucosal esophageal mass that was heterogeneous and invaded into the muscularis propria. Fine-needle aspiration (FNA) showed large cells with granular cytoplasm along with spindle nuclei. Cells were initially checked for CD117 stain alone and found to be negative. A follow-up CT-guided core needle biopsy revealed similar granular cells that were positive for S-100. She underwent a two-stage transhiatal esophagogastrectomy as the tumor circumferentially involved the cervical esophagus and was adherent to the trachea and recurrent laryngeal nerve bilaterally. At surgery, there were two additional foci palpable in the proximal stomach.

DISCUSSION AND CONCLUSION

As these tumors may have potential for malignant transformation and locoregional invasion, they should be considered while evaluating submucosal lesions of the esophagus even in young patients. A large number of granular cell tumors may be missed in the absence of S-100 staining, which should be requested when granular cells are seen on cytology obtained by EUS FNA as this can be a minimally invasive diagnostic modality for these tumors. Other foci should be sought at surgery as they have a propensity for locoregional spread.

Giant cell carcinoma of the lung impact of diagnosis and review of cytological features

Giant cell carcinoma of the lung is a specific type of lung carcinoma characteristically associated with a highly aggressive clinical behavior. This tumor comprises approximately 1-5% of all lung cancers, affecting a similar patient population as other primary pulmonary carcinomas. It is not routinely treated surgically, owing to the fact that it is metastatic at the time of diagnosis. The cytological diagnosis of this entity on aspiration biopsy has an appreciable impact on patient care. We retrospectively examined 15 cases of lung fine-needle aspirates in which a diagnosis of giant cell carcinoma or large cell carcinoma with giant cell features was made. We applied the criteria for cytological diagnosis of giant cell carcinoma previously set forth in the literature. In cases where there is a tissue diagnosis, we compared the results with the corresponding fine-needle aspirates and correlated them with patient survival. Conclusions are made regarding the reliability of the diagnostic criteria of this malignancy.

Primary Ewing sarcoma/PNET of the kidney: fine-needle aspiration, histology, and dual color break apart FISH Assay

A 34-year-old previously healthy Hispanic man presented with lower back pain. CT scan revealed an 8-cm space-occupying lesion in the superior pole of the left kidney with numerous small lytic lesions in the skull, vertebrae, ribs, and pelvic bones. CT-guided fine-needle aspiration biopsy revealed a high-grade primitive small round cell tumor with the tumor cells being strongly positive for CD99 and vimentin. The patient subsequently underwent a left nephrectomy. Fluorescence in situ hybridization analysis using a DNA probe for the Ewing Sarcoma breakpoint region 1 (EWSR1) on chromosome 22g12 revealed a rearrangement of the EWSR1 locus. The diagnosis of primary Ewing sarcoma/primitive neuroectodermal tumor of the kidney was established.

Primary vascular neoplasms unique to the spleen: littoral cell angioma and splenic hamartoma diagnosis by fine-needle aspiration biopsy

We report the fine-needle aspiration (FNA) biopsy diagnosis of two rare cases of primary vascular neoplasms unique to the spleen: a littoral cell angioma from a 31-yr-old Caucasian woman and a splenic hamartoma from a 46-yr-old black man. The cytologic features of splenic hamartoma and of littoral cell angioma of the spleen were described three times in cytologic literature: two were bench-top aspirates and one was FNA biopsy thought to be metastatic carcinoma. To the best of our knowledge, the current two cases were the first diagnosed by FNA biopsy. Our approach to the FNA biopsy diagnosis of these rare vascular neoplasms via compact cell block and immunohistochemistry is described. The differential diagnosis with other primary vascular splenic neoplasms is also discussed.

Interwoven dendritic processes of follicular dendritic cell sarcoma demonstrated on ultrafast papanicolaou-stained smears: a case report

BACKGROUND

Follicular dendritic cell (FDC) tumor is a rare tumor derived from accessory cells in the lymphoid follicles. FDC tumors are typically diagnosed on histology based on immunoreactivity to at least 1 of the FDC markers (CD21, CD23 or CD35) or based on the characteristic ultrastructural feature of long, interwoven, cytoplasmic, dendritic processes connected by desmosomes.

CASE

We observed novel cytologic features of FDC sarcoma in a liver fine needle aspirate of a 46-year-old man status post surgery and chemotherapy for FDC sarcoma, originating in the gastrointestinal tract with metastases to the liver, pancreas and spleen. In the Diff-Quik- and Papanicolaou-stained smears, the tumor cells presented in syncytial fragments as well as single cells, as previously reported in the cytologic literature. However, the single cells were interconnected to neighboring single cells via long, thin, threadlike cytoplasmic processes in ultrafast Papanicolaou (UFP)-stained smears. The tumor cells possessed multipolar cytoplasmic processes rather than unipolar ones, as previously reported.

CONCLUSION

The ultrastructural features of a web of interwoven, dendritic, cytoplasmic processes of FDC tumor was demonstrated for the first time on cytology. Observation of this feature may allow the diagnosis to be made on cytology prior to histology, immunohistochemistry or electron microscopy.

Diagnostic accuracy of follicular variant of papillary thyroid carcinoma in fine-needle aspirates processed by ultrafast Papanicolaou stain: histologic follow-up of 125 cases

BACKGROUND

Detection of follicular variant (FV) of papillary carcinoma (PC) of the thyroid is considered difficult in cytology. Various ancillary studies have been used to increase the sensitivity in the detection of FVPC in fine-needle aspiration (FNA). We previously reported that the clear nuclei of PC became conspicuous in Ultrafast Papanicolaou (UFP)-stained smears. This study reports our experience on using this UFP-induced artifact in the detection of FVPC.

METHODS

Over an 11-year period, 5637 ultrasound-guided thyroid FNAs were performed. All samples were smeared and air-dried. Diff-Quik stain was used to assess the colloid and UFP stain was used to study the nuclei.

RESULTS

Histologic follow-up was available from 125 cases. Of the 107 aspirates with diffuse "grape-like" watery clear nuclei, histologic follow-up showed 94 PCs, 8 follicular adenomas containing atypical nuclei, and 5 nonneoplastic lesions. Of the 18 aspirates with focal clear nuclei, histologic follow-up showed 6 PCs, 8 follicular adenomas, and 4 nonneoplastic nodules. As reported previously, histologic follow-up of 147 FNAs contained follicles with normal nuclei showed 107 true follicular neoplasms, 32 hyperplastic nodules, and 8 FVPC. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy in the detection of PC were 93.6%, 94.9%, 93.6%, 94.9%, and 94.3%, respectively, when follicular adenomas containing atypical nuclei were counted as encapsulated FVPC; and 92.6%, 85.6%, 80%, 94.9%, and 88.3%, respectively, when follicular adenomas containing atypical nuclei were counted as benign.

CONCLUSION

UFP stain is one of the options to increase the sensitivity of detection of FVPC in preoperative FNA, and to triage microfollicular nodules into those that require surgery no matter how small, and those which can be followed when small.

Distinguishing adenoid cystic carcinoma from cylindromatous adenomas in salivary fine-needle aspirates: The cytologic clues and their ultrastructural basis

The utilization of fine-needle aspiration (FNA) biopsy in salivary tumors is hindered by the reluctance of many cytopathologists to report adenoid cystic carcinoma (ACC) because its cylindromatous stroma is observed occasionally in pleomorphic adenoma (PA) and basal cell adenoma (BA), and a diagnosis of ACC results in radical surgery. The aim of this study is to identify dependable features to distinguish the look-alike entities and illustrate their ultrastructural base. We compared 20 cases of ACC to 15 cases of cylindromatous PA and 9 cases of BA. All were direct smears stained with Diff-Quik, hematoxylin and eosin, Papanicolaou, or Ultrafast Papanicolaou (UFP) stain. In addition to the presence of cylindromatous pattern, the amount of cytoplasm in the neoplastic cells and nuclear features were compared. Tissue was dissected from paraffin blocks and processed for electron microscopy in selected cases. The difference in nuclear features can be distinguished in UFP-stained smears and electron microscopy. The nuclei of ACCs were heterochromatic with coarse chromatin and irregular nucleoli, whereas the nuclei of PAs were euchromatic with fine chromatin and small compact nucleoli. The nuclei of BAs were hyperchromatic but finely textured. The cytoplasm of PAs was detectable with every stain at 40x objective, but the cytoplasm of BAs required UFP stain and 100x objective to be detected. The cytoplasm of majority of neoplastic cells of ACCs are invisible, because the thin rim of cytoplasm measured <1 microm ultrastructurally, well beyond the resolution of a light microscope. Rare cohesive fragment of epithelial cells in ACC have scanty blue cytoplasm in UFP stain and can be recognized as ductal cells. In conclusion, in our analysis of salivary tumors with a cylindromatous pattern, the seemingly naked nuclei of neoplastic cells with their coarse nuclear chromatin and irregular nucleoli, as revealed by the UFP stain, reliably distinguished ACC from cylindromatous adenomas.

Fine-needle aspiration cytology of pancreatoblastoma in a young woman: report of a case and review of the literature

Pancreatoblastoma is a rare tumor and has been reported only four times in the cytologic literature, three times in fine-needle aspiration (FNA) biopsy and once in an imprint of resected tumor. We are reporting the fourth case of FNA cytology with immunohistochemical and electron microscopic studies. The patient is a 24-yr-old African American woman, who presented with a pancreatic mass, hepatic masses, and abdominal lymphadenopathy. The aspiration smears of the liver mass showed a biphasic tumor composed of bland-appearing primitive spindled stromal fragments with "spider-web"-like long fibrils interconnecting with sharply angulated islands of cohesive epithelium. At high power, the epithelium is composed of medium-sized cells with round-to-oval vesicular nuclei with fine chromatin and one-to-two small nucleoli. The neuroendocrine component was demonstrated immunohistochemically with synaptophysin and chromogranin expressions. The acinar component and squamoid component were demonstrated ultrastructurally by the presence of 400-600 nm zymogen granules and tonofilaments. The literature was reviewed and the cytological features of all the four cases of pancreatoblastoma are summarized.

Clue to fine-needle aspiration diagnosis of pleural pneumocystoma: neovascularization and Langhans' giant cell reaction

Pneumocystis pneumonia is a common component of the acquired immunodeficiency syndrome (AIDS) in the United States. Extrapulmonary pneumocystosis, however, is much less common. Rare cases have been reported in lymph nodes, bone marrow, spleen, pleura, gastrointestinal tract, liver, common bile duct, pancreas, skin, thyroid, and eye. A 39-yr-old man with history of chest wall injuries from gunshot and stabbing presented with multiple pleural masses clinically suspicious of metastatic deposits from an unknown primary. Fine-needle aspiration biopsy of the largest pleural mass revealed extrapulmonary pneumocystis, which led to the diagnosis of AIDS. Similar to the previous reports of pneumocystis mass lesions in extrapulmonary sites, the current case is associated with exuberant vascular proliferation and Langhans' giant cell reaction. Neovascularization and histiocytic influx from the newly formed blood vessels and Langhans' giant cell reaction seem to be a common tissue reaction to the massive deposition of pneumocystis organisms in extrapulmonary sites in patients with AIDS.

Atypical papillary proliferation in gynecologic patients: a study of 32 pelvic washes

Papillary clusters in gynecologic pelvic washes frequently cause diagnostic challenges because they can be associated with borderline or malignant ovarian tumors, as well as benign pelvic diseases. The objective of our study was to review all pelvic washes with atypical papillary proliferation (APP) and investigate whether cytomorphology and/or immunohistochemistry on cell block could determine their origin. Thirty-two pelvic washes from 31 patients containing APP were reviewed and correlated with their corresponding gynecologic or pelvic disease. Previously obtained cell blocks with immunohistochemical (IHC) stains were reviewed also. Nine of 32 washes (28%) were overcalled as malignant and were from patients with 5 borderline serous ovarian tumors (BSTO), 1 ovarian follicular cyst, 1 serous cystadenofibroma, and 1 endometrial carcinoma with ovarian seromucinous cystadenoma. BSTO and endometriosis were the most common sources of APP. Cell blocks could not discriminate further the etiology of APP. Immunohistochemistry was performed rarely and not fully contributory. Caution in interpreting papillary groups and cytohistological correlation is recommended to prevent a high false positive rate.

Fine-needle aspiration cytology of epithelioid angiosarcoma: A diagnostic dilemma

A 28-year-old woman with a 2-yr history of unilateral chronic leg swelling, initially thought to be secondary to deep vein thrombosis, later thought to be due to congenital venous malformation, eventually developed a pelvic mass, which was biopsied by fine-needle aspiration. On the basis of cytologic features on smears, high-grade sarcoma was reported. The patient underwent surgery to resect the pelvic mass, which showed anastomosing vascular channels arising from external iliac vein in histology. However, the tumor cells unexpectedly showed strong and diffuse immunohistochemical expression of cytokeratin and epithelial membrane antigen. The case was sent for expert consultation, and the expert's opinion was epithelioid angiosarcoma. The expert's diagnosis was confirmed 2 yr later by local recurrence. The clinical presentation, cytology, histology, and immunohistochemistry of the current case and 15 other cases of epithelioid angiosarcoma found in the cytology literature are summarized. This case illustrates that morphology with clinicopathologic correlation tends to be a better guide than available special techniques.

Human T-lymphotropic virus type-1 related adult T-cell leukemia/lymphoma presenting as a parotid mass diagnosed by fine-needle aspiration biopsy

A 48-yr-old black woman with a history of blood transfusions for menorrhagia secondary to uterine fibroids but no known Caribbean association presented with a 6-wk history of a rapidly enlarging right parotid mass. At the time of presentation, she could not close her right eye. An aspiration biopsy showed small, medium, and large lymphoma cells with angulated nuclei, red macronucleoli, and basophilic cytoplasm with fine vacuoles. Flow cytometry indicated a (CD25(+)/CD7(-)) T-cell lineage, suggesting an human T-lymphotropic virus (HTLV) 1-related T-cell leukemia/lymphoma, which was confirmed by polymerase chain reaction (PCR)-based amplification on DNA extracted from fresh tissue with specific oligonucleotide primers for HTLV-1 DNA sequence. Histology showed interstitial infiltration and destruction of the parotid parenchyma by lymphoma cells without involvement of adjacent lymph nodes. Total body CT scan and magnetic resonance imaging (MRI) studies were negative for lymphadenopathy but showed liver metastasis. To our knowledge, this is the first reported case of HTLV-1-related primary parotid lymphoma as the initial presentation of adult T-cell leukemia/lymphoma.

Distinguishing well-differentiated hepatocellular carcinoma from benign liver by the physical features of fine-needle aspirates

Distinguishing well-differentiated hepatocellular carcinoma (HCC) from benign hepatic lesions is challenging for pathologists in limited diagnostic material such as needle-core tissue biopsy and fine-needle aspiration (FNA) biopsy. The objective of this study is to test a hypothesis that the fortification of liver by reticulin along single cell plates should protect benign hepatic lesions from breakdown by the force of aspiration and smearing, whereas the decreased reticulin in well-differentiated HCC would result in finely granular FNA smear. The study involved FNA biopsies of 67 cases of well-differentiated HCC and 109 cases of benign hepatic lesions, including cirrhosis (22), liver cell adenoma (8), steatosis (7), focal nodular hyperplasia (6), liver with cholestasis (6), and unremarkable liver sampled from nodular hepatic lesions consistent with the regenerative nodules (60). A slide with the most sample from each case by gross inspection was mixed together. Two observers blinded to the diagnoses were asked to separate the slides into two groups based on smear characteristics by gross inspection. Fragments of rigid fine-needle cores was present in 109 out of 109 cases of benign hepatic lesions but absent in 61 out of 67 cases of well-differentiated HCC, which presented as finely granular smears. The difference is statistically significant. (P<0.001, df=1, chi2=149.3). Using the physical characteristic of liver aspirates as the screening test for malignancy, the sensitivity is 91%, specificity is 100%, positive predictive value is 100%, negative predictive value is 94.8%, and efficiency is 96.6%. In conclusion, the smear characteristics of liver samples in FNA biopsy correlate to their reticulin status on histology. This physical characteristic can be used as the first clue to distinguish malignant and benign liver aspirates prior to microscopic examination.

Cytologic features and histologic correlations of microacinar and microtrabecular types of well-differentiated hepatocellular carcinoma in fine-needle aspiration biopsy

BACKGROUND

Well-differentiated hepatocellular carcinoma (HCC) in fine-needle aspiration (FNA) biopsy is characterized by trabeculae three or more cells thick wrapped by peripheral endothelium. The authors encountered another pattern that did not fulfill these classic criteria for malignancy yet was proven to be HCC in clinical follow-up. The objective of this study was to characterize the cytologic features of this pattern with histologic correlations.

METHODS

Over a period of 6.5 years, 14 of 123 cases (11.4%) of HCC from 428 liver aspirates showed the unusual pattern. Their cytologic features were compared with 14 cases of nonneoplastic liver on FNA smears that were processed with Ultrafast Papanicolaou stain, and their histologic features were compared on cell blocks with hematoxylin and eosin stain and reticulin stain.

RESULTS

The unusual type of well differentiated HCC in FNA smears was characterized by numerous, small hepatocytes with minimal nuclear atypia but reduced cytoplasm, grouped together in microacini of five or more cells and microtrabeculae one or more cells thick of irregular thickness with no apparent peripheral endothelium. Transgressing capillaries were found when the smears were inspected carefully. In histology nine cases that were the compact type of HCC, two cases that were the microacinar type of HCC, and three cases that were the microtrabecular type of HCC. All FNAs showed deficient reticulin framework. All 14 cases of nonneoplastic liver aspirate were characterized by the presence of large tissue fragments that were resistant to smearing.

CONCLUSIONS

Well differentiated HCC may present as microtrabeculae of irregular thickness one or more cells thick with inapparent peripheral endothelium or as microacini mimicking neuroendocrine carcinoma.

Risk of Malignancy in Follicular Neoplasms without Nuclear Atypia: Statistical Analysis of 397 Thyroidectomies

OBJECTIVE

To determine how to triage patients with a follicular neoplasm (FN), without nuclear atypia reported by fine-needle aspiration, on the basis of risk factors.

METHODS

The age, sex, tumor size, and cell type of 397 patients who underwent thyroidectomy for follicular carcinoma (FC) or follicular adenoma between 1991 and 2001 were analyzed statistically. The likelihood ratio and probability of FC for various combinations of tumor size, sex, and cell type were estimated with use of Bayes' theorem.

RESULTS

FC was significantly associated with tumor size >2.1 cm (P = 0.048), male sex (P = 0.0007), and Hürthle cell type (P<0.0001). The mean size of minimally invasive FC was significantly smaller (2.9 cm versus 4.8 cm; P = 0.004) and the mean patient age was significantly younger (47.6 years versus 61.0 years; P = 0.003) than for widely invasive FC. The lowest probability (0.31%) for FC was in female patients with a small (< or = 2.1 cm) micro-follicular FN reported by a cytopathology practice with 10% accuracy of true FN at surgical intervention, whereas the highest probability (29.5%) for FC was in male patients with a large (>2.1 cm) Hürthle cell neoplasm reported by a cytopathology practice with 70% accuracy of true FN at surgical intervention.

CONCLUSION

Although an estimate of probability for FC based on age, sex, thyroid nodule size, and cell type is provided in this study for patients diagnosed with FN without nuclear atypia on fine-needle aspiration, the variability of the accuracy in cytopathology practice makes it difficult to change the current treatment paradigm, which requires carefully planned prospective studies with long-term follow-up.

Should cytopathologists stop reporting follicular neoplasms on fine-needle aspiration of the thyroid?

BACKGROUND

As the consequence of the decreasing incidence of follicular thyroid carcinoma (FC), one wonders whether cytopathologists should stop reporting follicular neoplasms in fine-needle aspiration (FNA) of the thyroid to minimize unnecessary thyroidectomies, if the follicular variant of papillary carcinoma (FVPC) has been excluded.

METHODS

Over a 6-year-period, 2667 ultrasound-guided FNAs of the thyroid were performed at our practice. A total of 246 nodules (9.2%) were reported as follicular neoplasms, using abundant blood as the diagnostic clue. All FNA specimens were prepared and reported by one cytopathologist and the final pathology was reported by surgical pathologists in various hospitals in New York City.

RESULTS

The histologic follow-up was available for 147 cases and showed 5 cases of widely invasive FC (3.4%), 10 cases of minimally invasive FC (6.8%), 8 cases of FVPC (5.4%), 92 cases of follicular adenoma (62.6%), and 32 cases of nonneoplastic nodules (21.8%).

CONCLUSIONS

FVPC cannot be excluded completely from follicular neoplasms by FNA because of the patchy distribution of papillary carcinoma nuclei in the encapsulated variant. Widely invasive FC still exists and may cause considerable morbidity in patients as young as the third decade of life. It is the opinion of the authors that cytopathologists should continue reporting follicular neoplasms in FNA of the thyroid.

Metaplastic carcinoma of the breast with rhabdomyosarcomatous element: aspiration cytology with histological, immunohistochemical, and ultrastructural correlations

We studied a metaplastic breast carcinoma with a rhabdomyosarcomatous element from a 62-yr-old woman. In the fine-needle aspirates processed by Ultrafast Papanicolaou stain, there were small undifferentiated cells with scanty cytoplasm and differentiated cells with red macronucleoli and abundant cytoplasm. Some differentiated cells contained a brown inclusion with a blue rim. Ultrastructurally, the brown inclusion correlated to a central aggregate of sarcomeres and the blue rim correlated to actin filaments surrounding the sarcomeres. The differentiated cells without cytoplasmic inclusions expressed cytokeratin and contained tonofilaments. A transitional cell type containing both sacromeres and tonofilaments was absent. Immunohistochemically, the small undifferentiated cells expressed vimentin diffusely and showed >90% MIB-1 proliferating index, whereas the differentiated cells expressed cytokeratin, actin, or myoglobin and had virtually absent MIB-1 nuclear labeling. Histologically, the small cells were more concentrated along the capsule and the large cells were more concentrated in the center of the tumor. These findings suggest the bidirectional differentiation of the small undifferentiated cells into carcinoma cells and rhabdomyosarcoma cells in this tumor.

Long microvilli of mesothelioma are conspicuous in pleural effusions processed by Ultrafast Papanicolaou stain

BACKGROUND

The differentiation of malignant epithelial mesothelioma, nonmucinous pulmonary adenocarcinoma, and mesothelial hyperplasia by direct light microscopic examination is challenging. The detection of long microvilli, an ultrastructural feature unique for malignant epithelial mesothelioma, requires immunolabeling of epithelial membrane antigen to be visible by light microscopy. The purpose of this study is to report that this feature is now made conspicuous enough to be detected by light microscopy by a different approach in cytologic processing.

METHODS

The study includes 9 cases of mesothelioma, 50 cases of mesothelial hyperplasia, and 50 cases of nonmucinous pulmonary adenocarcinoma. Direct smears were made from the sediments of fresh or refrigerated effusions, air dried, rehydrated with normal saline for 30 seconds to create retraction halos, and processed with the Ultrafast Papanicolaou stain (UFP).

RESULTS

Long microvilli in thick bundles as well as short, fine projections radiating from the free surface of the epithelial mesothelioma cells were observed within the retraction halos in pleural effusions processed by UFP. These features were not observed in the UFP-processed hyperplastic mesothelial cells or in the pulmonary nonmucinous adenocarcinoma cells.

CONCLUSION

Direct visualization of long microvilli via UFP may aid in the distinction of malignant mesothelioma from mesothelial hyperplasia and adenocarcinoma before immunohistochemical and electron microscopic studies are performed.

Aspiration cytology of cystic carcinoma of the breast

Cystic carcinomas of the breast are rarely encountered in fine-needle aspiration (FNA) biopsies. The most common entities comprise intracystic papillary adenocarcinoma, ductal adenocarcinoma with cystic degeneration including comedo forms of ductal adenocarcinoma in situ, medullary carcinoma, squamous carcinoma, and cystic hypersecretory ductal adenocarcinoma. The cytologic diagnosis is often hampered by sparse cellularity, abundant obscuring blood, necrotic debris, and degenerative changes in diagnostic cells. We report on the cytologic features of 10 cases of cystic carcinoma, including 12 FNA biopsies with radiologic and surgical correlation. The original cytologic diagnoses for these cases were: benign (2 cases), atypical (2 cases), suspicious (3 cases), and positive for malignant cells (3 cases). On repeat FNA, one benign case and one atypical case were reclassified, respectively, as atypical and suspicious for carcinoma. The follow-up diagnoses were 5 intracystic papillary adenocarcinomas and 5 cystic ductal adenocarcinomas. Despite 2 false-negative cases, all cases were adequately managed. Correlation with clinical and radiologic findings and direct sampling of any solid component of these cystic neoplasms are crucial in diagnosis and management.

Factors influencing the detection of uterine cancer by suction curettage and endometrial brushing

OBJECTIVE

To analyze the factors that influence the detection of uterine cancers by Pipelle and Tao Brush endometrial sampling devices.

STUDY DESIGN

Seventy-nine Pipelle currettages were followed by Tao Brush sampling. The curettage specimens were fixed in formalin for histology and reported by surgical pathology, whereas the Tao Brush specimens were fixed in CytoRich Red for histology and cytology and reported by cytopathology. Uterine size and features of residual tumors were obtained from hysterectomy reports. Follow-up for clinically benign cases ranged from 16 to 52 months (mean, 33.7; median, 34).

RESULTS

There were 10 uterine cancers and 9 hysterectomies. Five cases of centrally located adenocarcinoma, ranging from 0.4 to 3 cm, were detected by both samplers. Additionally, a Tao Brush sampled an adenocarcinoma located near the cornu. An endometrial stromal sarcoma found with a Tao Brush was reported as necrotic tissue by Pipelle. Both samplers missed a microscopic focus of adenocarcinoma, an in situ adenocarcinoma in a polyp and a large leiomyosarcoma.

CONCLUSION

The size and type of tumor and its location within the uterine cavity, the mechanism of sampling and preparation method influence the detection of uterine cancer by the Pipelle and Tao Brush.

Ultrafast Papanicolaou stain and cell-transfer technique enhance cytologic diagnosis of Hodgkin lymphoma

Diagnosis of Hodgkin lymphoma (HL) by fine-needle aspiration (FNA) is often hampered by aspirated blood that camouflage scattered Hodgkin cells and Reed-Sternberg (HRS) cells, and the absence of HRS cells in the smears submitted for immunophenotyping. The objective of this study was to develop a simple protocol to overcome these problems. The visibility of HRS cells in Diff-Quik, traditional, and Ultrafast Papanicolaou (UFP) stains in FNA smears were compared in 73 cases of HL. HRS cells were found to be most visible in UFP because of the hemolysis of aspirated blood and the highlighting of HRS cells by the red-staining nucleoli. UFP-stained smears containing HRS cells were subsequently immunophenotyped via the cell-transfer technique. UFP staining was found to have no deleterious effect on the immunoreactivity of cellular CD15 and CD30 antigens of HRS cells. This simple protocol enhances the cytologic diagnosis of HL, feasible even with a single smear.

Fine-needle aspiration cytology of unusual germ cell tumors of the mediastinum: atypical seminoma and parietal yolk sac tumor

A 30-yr-old man presented with a mediastinal germ cell tumor that combined the histologic pattern of seminoma with the immunohistochemical profile of embryonal carcinoma (beta-HCG+/PLAP-). In FNA smears, this atypical seminoma presented as fragile large cells with scanty cytoplasm, vesicular nuclei, irregular and indistinct nucleoli, scattered singly and in loosely cohesive fragments without the characteristic lymphocytic or tigroid background. The cytologic features were more suggestive of a poorly differentiated carcinoma than seminoma, potentially leading to misdiagnosis and mismanagement. The second case was a 51-yr-old female smoker who presented with mediastinal parietal yolk sac tumor with extension to the lung, a rare occurrence, and contrary to the clinical impression of lung cancer with hilar lymph node metastasis. This case illustrates the value of using the unique cytologic features of parietal yolk sac tumor, i.e., the abundant, viscous, stringy metachromatic extracellular hyaline material associated with the tumor cells in reaching the accurate diagnosis.

Epithelioid gastrointestinal stromal tumor of the stomach with liver metastases in a 12-year-old girl: aspiration cytology and molecular study

Gastrointestinal stromal tumor (GIST), a stromal tumor of the gastrointestinal tract defined as CD117 (c-kit)-positive neoplasm, occurs primarily in adults. GIST with CD117 (c-kit) mutation and certain cytogenetic abnormalities is associated with malignancy, though a definite relationship between prognosis and molecular alterations remains to be elucidated. We report the cytologic features of an epithelioid GIST arising in the stomach of a child and metastatic to the liver, and the molecular mutational analysis of both the primary gastric tumor and the liver metastasis. Literature of pediatric GISTs was also reviewed. Fine needle aspiration of the liver metastasis, processed by Ultrafast Papanicolaou stain, showed fragments of cohesive small epithelioid cells with bland oval nuclei and unipolar cytoplasm transected by capillaries. Immunohistochemically, all nodules in the stomach and liver expressed CD117 (c-kit). Interestingly, some of the gastric tumor clusters were uniformly CD34 positive, whereas others were uniformly CD34 negative, suggesting heterogeneity of tumor clones. The presence of neurosecretory granules further subtyped the tumor into gastric autonomic nerve tumor (GANT). Molecular mutational analysis, performed in both the gastric tumor and the liver metastasis, showed no sequence abnormality in exons 9, 11, and 13 of CD117 (c-kit). Cytogenetic study revealed normal karyotype. These features might suggest a different molecular mechanism leading to malignancy in certain GISTs arising in children.

Thyroid microcarcinoma: fine-needle aspiration diagnosis and histologic follow-up

The increased sensitivity of many imaging modalities (ultrasound, computed tomography scan, magnetic resonance imaging) has resulted in the identification of thyroid nodules, measuring 1 cm or less. Usually these small lesions are regarded as incidental and are not sampled by fine-needle aspiration (FNA). However, some of these lesions undergo FNA because of suspicious radiology findings (multifocality, calcification, etc) or in patients with a history of radiation to the head and neck region. We present FNA findings and histologic follow-up of 39 thyroid nodules that measured 1.0 cm or less. All FNAs were performed under ultrasound guidance. The lesions ranged in size from 0.2 to 1.0 cm. Twenty-two lesions were diagnosed as papillary carcinoma (PTC), 4 as medullary carcinoma (MC), and 13 as suspicious for PTC on FNA. Histologic follow-up showed PTC in 35 and MC in 4 cases; 11 PTC were multifocal (31%) and lymph node metastases were present in 8 (16%) cases. Ultrasound-guided FNA is effective in the sampling of thyroid cancers that are 1.0 cm or less. The present study shows that some of these lesions can be clinically significant.

TIA-1+ cytotoxic large T-cell lymphoma of the mediastinum: case report

A 52-year-old previously healthy Caucasian woman presented with superior vena cava syndrome, secondary to compression of a bulky anterior mediastinal mass involving the right lung. Fine-needle aspiration biopsy of the mediastinum yielded large epithelioid cells intermingled with small mature lymphocytes. The epithelioid cells are LCA positive, expressing cytoplasmic CD3 diffusely and TIA-1 focally, but negative for EMA, CD4, CD8, CD15, CD20, CD30, and CD56. The TIA-1+ cytoplasmic granules correlated to the azurophilic granules in Diff-Quik-stained cells, pink granules in Ultrafast Papanicolaou-stained cells, and dense core granules in electron microscopy. In situ hybridization for Epstein-Barr viral RNA was negative. The background small lymphocytes were composed of a majority of CD4+ T-lymphocytes and minority of CD8+ T-lymphocytes. The patient responded well to six cycles of CHOP chemotherapy, followed by radiation with a total dose of 4140 cGy delivered to the mediastinum in 23 fractions. On the chest X-ray taken 6 mo later, there was minimal apical fibrosis with no evidence of an acute intrathoracic pathology. To the best of our knowledge, this case may be the first report of cytotoxic large T-cell lymphoma of the mediastinum.