Medullary thyroid carcinoma presenting as rectangular cell type on fine‐needle aspiration

Medullary thyroid carcinoma typically presents as dyscohesive plasmacytoid, spindled, or polygonal cells on fine‐needle aspiration smears. We recently encountered a case of sporadic medullary thyroid carcinoma that presented as a hypercellular aspirate composed of cohesive aggregates of rectangle‐shaped cells. The case was mistakenly reported as a hypercellular follicular neoplasm on cytology. Subsequent thyroidectomy revealed medullary carcinoma. We draw attention to this distinctive rectangular cell type as an additional morphology for medullary thyroid carcinoma. Diagn. Cytopathol. 2009. © 2009 Wiley‐Liss, Inc.     

Fine‐needle aspiration cytology of basaloid squamous cell carcinoma and small cell carcinoma—A comparison study

The cytopathologic diagnosis of basaloid squamous cell carcinoma can be problematic as there are several components of the differential diagnosis that share common cytomorphologic features. In this study, we report the fine‐needle aspiration (FNA) findings of 16 basaloid squamous cell carcinoma cases and compare those cases to 16 cases of small cell carcinoma. To our knowledge, this is the largest series of basaloid squamous cell carcinoma FNA cases ever reported. The following cytomorphologic features were compared for both tumors: cohesive tissue fragments, single cells, adenoid cystic‐like features (cribriform pseudoglandular lumina with hyaline materials), necrosis, nuclear size, nuclear molding, nucleoli, cytoplasm, and the presence of single keratinized cells. Adenoid cystic‐like features and the presence of single keratinized cells were specific for basaloid squamous cell carcinoma (P < 0.05). Diagn. Cytopathol. 2013. © 2011 Wiley Periodicals, Inc.     

Endoscopic ultrasound‐guided fine‐needle aspiration diagnosis of merkel cell carcinoma metastatic to the pancreas

Merkel cell carcinoma (MCC) is a rare and highly aggressive primary neuroendocrine carcinoma of the skin with a high propensity for local, regional, and distant spread. Distant metastasis of MCC to the pancreas is uncommonly seen and may impose a diagnostic challenge cytologically. Here we report a case of MCC with pancreatic metastasis, which was diagnosed by endoscopic ultrasound‐guided fine‐needle aspiration (EUS‐FNA). The aspirates revealed both single and clustered epithelial cells with scant cytoplasm and round nuclei with stippled chromatin and inconspicuous nucleoli. Immunocytochemically, the tumor cells were positive for CK20, synaptophysin, CD56, and CD117. The neoplastic cells were also identified by flow cytometry as non‐hematopoietic cells which were positive for CD56 and negative for CD45. To our knowledge, this is only the second case report of MCC metastatic to the pancreas diagnosed by EUS‐FNA. There have been several reports of MCC metastatic to the pancreas diagnosed only at the time of surgical resection. However, a preoperative diagnosis allows for appropriate management while sparing a patient the morbidity of unnecessary procedures. Diagn. Cytopathol. 2014;247–252. © 2012 Wiley Periodicals, Inc.     

Small cell mesothelioma: A rare entity and diagnostic pitfall mimicking small cell lung carcinoma on fine‐needle aspiration

Small cell mesothelioma (SCM) is an extremely rare variant of epithelioid mesothelioma that can be mistaken for other forms of small round blue cell tumors, particularly small cell lung carcinoma (SCLC). Here, we describe a fine‐needle aspiration (FNA) from a pleural lesion in a 75‐year‐old man with a history of known asbestos exposure. The FNA revealed cohesive clusters of uniform small round blue cells with high nuclear‐to‐cytoplasmic ratio, finely powdery chromatin, small inconspicuous nucleoli, and scant amount of cytoplasm. Mitoses were infrequent and nuclear molding was absent. Immunochemical profile supported a mesothelial origin, which was later confirmed by pleurectomy with a diagnosis of SCM. This report demonstrates the difficulties in cytologic evaluation of lung FNAs in differentiating SCM from SCLC or other small round blue cell tumors. As therapy differs for SCM, early recognition of the cytologic features is essential in making the correct diagnosis needed for appropriate clinical management. Diagn. Cytopathol. 2016;44:526–529. © 2016 Wiley Periodicals, Inc.     

Fine‐needle aspiration cytology of adenoid cystic carcinoma of the breast

Adenoid cystic carcinoma (ACC) of the breast is a rare variant of breast malignancy and has a better prognosis than its counterpart in the salivary glands. In this communication, our experience with seven cases of ACC of the breast is presented in which the diagnosis was established on fine‐needle aspiration cytology (FNAC). The cytologic samples in all cases were cellular and featured three‐dimensional clusters of uniform ductal epithelial cells with cystic spaces, bland nuclei, fine chromatin, and scanty cytoplasm arranged around spheres or cores of homogenous material. The cytodiagnosis of ACC in all cases correlated with subsequent examination of cell blocks of the aspirate and tissue. The cytodiagnostic criteria for ACC of the breast which are useful in a correct FNAC diagnosis are discussed. Diagn. Cytopathol. 1999;20:82–84. © 1999 Wiley‐Liss, Inc.     

Mucinous breast carcinoma metastatic to thyroid gland: Report of a case diagnosed by fine‐needle aspiration cytology

Mucinous breast cancer is a slow‐growing neoplasm, which has fewer lymph node metastases and favorable prognosis compared with invasive breast cancer no special type. The hematogenous spread of breast mucinous carcinoma is very rare. Though breast cancer involving thyroid has been reported before, there is still no report about thyroid metastatic breast mucinous carcinoma in the literature. Recently by performing thyroid fine‐needle aspiration, a 58‐year‐old woman who had breast cancer 13 years ago was diagnosed as thyroid metastatic mucinous breast carcinoma, cellular variant with neuroendocrine differentiation. For this patient, the thyroid was the only involved site without widespread metastatic diseases, so thyroidectomy and the right cervical lymph nodes dissection were performed to make better survival. As a result, the patient had not shown any signs of recurrence 9 months after the thyroid surgery.     

Primary pure squamous cell carcinoma of the breast diagnosed by fine-needle aspiration cytology: a case study using liquid-based cytology

Pure primary squamous cell carcinoma (SCC) is an extremely rare type of breast tumor. We report one of such cases in a 32-year-old woman, diagnosed by fine-needle aspiration cytology (FNAC). Aspiration smears were characterized by squamous cells, both isolated and in aggregates, at various stages of maturation. The tumor was excised, and the histologic sections confirmed the cytologic diagnosis. Pure primary SCC of the breast has a distinctive cytomorphologic appearance, and diagnosis of this tumor by FNAC is possible. For its diagnosis, the exclusion of SCC of local cutaneous structures and metastasis of distant squamous carcinoma are mandatory.     

Fine‐needle aspiration of tubulocystic renal cell carcinoma

We report two cases of tubulocystic renal cell carcinoma, a rare renal tumor the cytology of which has not been previously reported. Both aspirates were cellular and contained large sheets of cells with abundant granular cytoplasm, distinct cell borders and intracellular windows, distinct to prominent nucleoli, rare intracytoplasmic vacuoles, and rare nuclear grooves. Cells with variable amounts of cytoplasm were also arranged in small groups, some of which resembled spherules. The large sheets of cells with windows appeared specific for tubulocystic carcinoma; the spherules could easily be confused with a papillary renal cell carcinoma.     

Fine‐needle aspiration biopsy of HPV‐related squamous cell carcinoma of the head and neck: Current ancillary testing methods for determining HPV status

Human papillomavirus (HPV)‐related head and neck squamous cell carcinoma (HNSCC) is a unique form of carcinoma that largely arises from the tonsillar tissue in the oropharynx. These tumors often present with cervical lymphadenopathy resulting in a fine needle aspiration (FNA) biopsy. Use of the cytology specimen to determine the HPV‐status has significant prognostic and treatment implications as HPV‐related tumors have a more favorable prognosis and response to nonsurgical therapies. While several different ancillary testing methods are available that have proven effective for determining HPV status in FNA specimens from HNSCCs, there is currently no consensus regarding HPV testing in this setting. Diagn. Cytopathol. 2017;45:221–229. © 2016 Wiley Periodicals, Inc.     

Metastatic small cell osteosarcoma to the liver: A diagnostic pitfall for fine‐needle aspiration cytology

We report the fine‐needle aspiration cytology of a case of metastatic small cell osteosarcoma to the liver with rosette formation, originating from distal femur, in a 36‐year‐old female. The aspirate of the liver metastases revealed a relatively monomorphic population of mitotically active small blue round cells arranged in clusters with prominent rosette formation simulating a neuroendocrine carcinoma or other rosette‐forming small round cell tumors such as Ewing sarcoma. No extracellular mineralized matrix material was present. Comparison of the liver aspirate with the biopsy from the distal femoral lesion was crucial in reaching the correct diagnosis of metastatic small cell osteosarcoma with rosette formation. This is a potential diagnostic pitfall, particularly if interpreted without the knowledge of a suspected primary bone tumor. Diagn. Cytopathol. 2014;42:161–164. © 2012 Wiley Periodicals, Inc.     

Fine‐needle aspiration cytology and immunohistology of low‐grade adenosquamous carcinoma of the breast

Low‐grade adenosquamous carcinoma of the breast (LASCB) is a relatively recently‐described, rare histotype of breast cancer that has a favorable prognosis. Its principal microscopic features are the presence of “syringoid” (“tadpole”‐shaped) ductal profiles of tumor cells, a bland and modestly cellular stromal background, and the variable presence of keratinizing (“epidermoid”) cell groups. As such, the basic image of LASCB is quite similar to that of microcystic adnexal or adenosquamous carcinoma of the skin or “syringomatous adenoma” of the nipple. We report the fine‐needle aspiration cytologic (FNA) attributes of this neoplasm, as well as its immunohistochemical characteristics and differential diagnosis. Diagn. Cytopathol. 1999;20:13–18. © 1999 Wiley‐Liss, Inc.     

Value of P63 and CK5/6 in distinguishing squamous cell carcinoma from adenocarcinoma in lung fine‐needle aspiration specimens

The current FDA‐approved standard of care for nonsmall cell lung cancer is Carboplastin/Taxol/Avastin based upon an impressive survival benefit; however, patients with squamous carcinoma (SQCC) cannot receive Avastin because of a 30% mortality rate due to fatal hemoptysis. In this study we evaluated the role of cytomorphology and immunohistochemistry in differentiating SQCC from adenocarcinoma (ADC) in lung FNA specimens. The case cohort included 53 FNA cases of nonsmall cell lung carcinoma with surgical pathology follow‐up. All FNA specimens were reviewed independently by a panel of cytopathologists to differentiate between SQCC and ADC. The cell block material was available in 23 cases (11 ADC and 12 SQCC) to perform immunohistochemical stains for TTF‐1, CK7, CK20, P63, and CK5/6. On surgical resection, 35/53 (66%) cases were diagnosed as ADC and 18/53 (34%) as SQCC. The number of cases classified correctly on the basis of cytomorphology was 66% for ADC and 53% for SQCC (combined accuracy 60%). By immunohistochemical staining, 14/23 (61%) cases expressed TTF‐1. Nine cases were TTF‐1 negative; eight of the TTF‐1 negative cases (89%) were SQCC. Twenty‐three cases expressed CK7 (87%); one ADC case (4%) showed focal CK20 positivity. Both P63 and CK5/6 expression was seen in 9/12 (75%) SQCC cases; none of the ADC cases showed this dual expression. Cytomorphology alone may not be able to stratify all cases of nonsmall cell lung carcinoma into ADC and SQCC in FNA specimens. The immune‐panel of TTF‐1, CK7, CK20, P63, and CK5/6 is useful in differentiating SQCC from ADC. Diagn. Cytopathol. 2009. © 2009 Wiley‐Liss, Inc.     

Papillary thyroid carcinoma with atypical histiocytoid cells on fine‐needle aspiration

Although papillary thyroid carcinoma (PTC) usually has classic cytological characteristics on fine‐needle aspiration (FNA), it can present rarely with aberrant features resembling those of histiocytes in a cystic nodule. The aim of the current study was to describe PTC with atypical histiocytoid cells and distinguish it from benign histiocytes. A retrospective computerized search for FNAs with atypical features suggestive of PTC and cystic degeneration was performed, and if available, the corresponding resection specimens were compared. Four cases met the criteria for FNAs and three had surgical pathology follow‐up, which showed PTC. One aspirate had some features typical of PTC, but the remaining FNAs had atypical histiocytoid cells, which had traits intermediate between those of PTC and histiocytes. Large cell size, pseudoinclusions, nuclear grooves, and multiple well‐defined vacuoles in atypical histiocytoid cells favor PTC over benign histiocytes. Ancillary immunocytochemical studies can also be useful in confirming the diagnosis. Histiocytic cells are frequently present in thyroid aspirates, and occasionally, they have atypical features that represent an unusual presentation of PTC. Closer examination of these cells can provide diagnostic clues for preventing false‐negative diagnosis of PTC. Diagn. Cytopathol. 2009. © 2009 Wiley‐Liss, Inc.     

Value of combined use of fine‐needle aspiration and core needle biopsy in palpable breast tumors performed by pathologist: Institut Curie experience

The aim of this study was to determine the accuracy of fine‐needle aspiration (FNA) and core needle biopsy (CNB) for palpable breast tumors (PBTs). FNA and CNB of 492 PBTs from 477 patients were analyzed. Tumors were malignant in 473 cases and benign in 19 cases. There was a strong correlation (P > .05) between FNA and CNB in terms of malignancy. Among 473 malignant tumors, FNA had better accuracy and less unsatisfactory results (95.6%; 2.7%) than CNB (94.9%; 4.9%). Among 19 benign tumors, CNB was accurate in 100% compared to 94.7% using FNA. There were only two (0.4%) cases where result was unsatisfactory by both FNA and CNB. NPV was 56.3% for FNA, 43.2% for CNB, and 95.0% for FNA and CNB combined. Sensitivity was 97.0% for FNA, 94.7% for CNB, and 99.8% for FNA and CNB combined. PPV and specificity was 100% for FNA and CNB both separately and combined. Combined use of FNA with CNB is an optimal diagnostic method for PBTs. In our opinion, this should be recommended as standard for diagnosis of PBTs.     

Laryngeal chondrosarcoma mimicking medullary thyroid carcinoma on fine‐needle aspiration cytology: A case report of a diagnostic pitfall

Chondrosarcoma (CS) of larynx is a rare laryngeal tumor accounting about 1% of laryngeal malignancies. When CS arises from thyroid cartilage, it may clinically present as a thyroid nodule. Here we report a rare case of CS of thyroid cartilage misinterpreted as medullary thyroid carcinoma. The main aim of this case report is to emphasize the important role of accurate clinical history, appropriate physical examination, and proper localization of the tumor and clear definitive imaging in conjunction with interpretation of cytologic smears. When any of these roles are unclear, it may result in misinterpretation of the cytologic smears. In these unusual circumstances, when cytomorphologic features does not completely fit an entity, communication with the physician and the consideration of a broad differential diagnoses in the head and neck pathology may lead to correct diagnosis and avoid diagnostic pitfalls. Also in certain conditions, ancillary studies including laboratory tests are necessary for definitive classification.     

Cytodiagnostic patterns of metaplastic breast carcinoma in aspiration samples: A study of 14 cases

Metaplastic breast carcinomas (MBCs) are not only uncommon neoplasms but also show a myriad of cytomorphologic patterns in aspiration samples. These tumors comprise less than 5% of breast malignancies and have an uncertain prognosis. In this study, the fine‐needle aspiration cytologic features of 14 MBCs with the identification of two distinct malignant cell populations are presented, based on which a definitive diagnosis was possible in 12 of the 14 cases. In the remaining 2 cases the diagnosis of MBC was substantiated after study of cell blocks from the aspirate, which were made in all the cases. Furthermore, the diagnosis of MBC was also confirmed subsequently on tissue examination. The various combinations of patterns included malignant ductal, squamous, and sarcomatous (including heterologous) elements and multinucleated osteoclastic giant cells. As a result of this study, it was felt that if malignant breast aspirates on careful examination show two or more distinct neoplastic elements, the diagnosis of MBC may be possible. Diagn. Cytopathol. 1999;20:10–12. © 1999 Wiley‐Liss, Inc.     

Metastatic ductal carcinoma of the breast to the thyroid gland diagnosed with fine needle aspiration: A case report with emphasis on morphologic and immunophenotypic features

Metastases to the thyroid are uncommon [<0.2% of thyroid fine needle aspirations (FNA)]. Of metastases to the thyroid, breast carcinoma is relatively common. The diagnosis of metastasis to the thyroid has important therapeutic and prognostic implications. To our knowledge, a morphologic and immunophenotypic comparison of metastatic ductal carcinoma of the breast and primary thyroid carcinomas has not been reported. Here, we report the case of a 37‐year‐old female with a history of metastatic ductal carcinoma of the breast (modified Bloom‐Richardson grade 2; ER+, PgR+, HER2+) diagnosed 6 years prior. She developed hoarseness, prompting a CT scan. Multiple thyroid nodules were found, including a 1.5 cm hypoechoic, solid, irregularly‐shaped nodule. On FNA, cells were arranged singly and in crowded groups, varied in size and degree of pleomorphism, and exhibited rare nuclear grooves, inconspicuous nucleoli, and rare intracytoplasmic lumina with no nuclear pseudoinclusions or colloid (Figs. 1A and B). These findings raised the differential of papillary thyroid carcinoma (Fig. 1C), follicular neoplasm (Fig. 1D), medullary carcinoma (Fig. 1E), parathyroid (Fig. 1F), and metastatic breast carcinoma. Immunostaining for GATA‐3 (+), ER (+), PAX‐8 (?), and TTF‐1 (?) was consistent with metastatic breast carcinoma (Fig. 2). We conclude that metastatic breast carcinoma to the thyroid may morphologically mimic primary thyroid carcinoma on FNA; a panel of immunomarkers, such as GATA‐3, hormonal marker(s), PAX‐8, and TTF‐1, may be useful in some cases. GATA‐3 immunostaining for metastatic breast carcinoma was helpful in our case and has not been previously reported in a thyroid metastasis sampled by FNA. Diagn. Cytopathol. 2016;44:530–534. © 2016 Wiley Periodicals, Inc.     

Cytomorphologic features of fine‐needle aspiration of liposarcoma

The cytomorphologic features of fine‐needle aspirates (FNA) of liposarcomas have not been fully characterized. In the current study, we attempted to identify cytological attributes of liposarcoma in FNA. Twelve FNAs of histologically proven liposarcomas were used for this study. They included 10 myxoid and two well‐differentiated liposarcomas. Four cytological criteria were chosen for evaluation. These included a complex capillary network, increased cellularity, the presence of a metachromatic stroma for myxoid liposarcoma, and finally the identification of lipoblasts. Eighteen FNAs of lipomas and 17 FNAs of nonlipomatous soft‐tissue sarcomas were used as controls for evaluation of the same features. The diagnosis of liposarcoma had been rendered on FNA in 7 cases (58%). The diagnosis was suggested in 3 cases (25%), and a suggestion of sarcoma was rendered in 2 cases. Complex capillary networks were identified in 9 of 12 cases (75%); this was seen in 8 of the 10 myxoid liposarcomas and 1 of the 2 well‐differentiated neoplasms. Increased cellularity was seen in 7 of 12 cases (58%), metachromatic stroma was seen in 3 of 12 cases (25%), and lipoblasts were identified in 4 of 12 cases (33%). None of the lipomas or sarcomas exhibited a complex capillary network. When capillaries were identified in lipomas, they were straight, with minimal branching. The lipomas did not show evidence of increased cellularity in any cases. Metachromatic stroma was more frequently seen in the nonlipomatous sarcomas than in the liposarcomas. No lipoblasts were identified in any of the control FNAs. Diagn. Cytopathol. 1999;20:67–69. © 1999 Wiley‐Liss, Inc.