Striated duct adenoma: The cytological description of a rare entity.

INTRODUCTION: Striated duct adenoma is a benign salivary gland tumour recently recognized by the World Health Organization. To date, no report has described the cytological features of this entity. MATERIALS AND METHODS: We report the case of a 60-year-old woman with a tumour in the right parotid gland with a diameter greater than 2.4 cm confirmed by imaging tests. RESULTS: Two fine-needle aspiration cytologies (FNAC) were performed with inconclusive results, reporting epithelioid and spindle-shaped cellularity, with little stroma, and nuclei with abundant pseudoinclusions. Myoepithelioma and Schwannoma were proposed as differential diagnoses. An immunocytochemical panel was performed, showing positivity for S-100, SOX10, CK7 and vimentin, and negativity for both myoepithelial (p63 and calponin) and thyroid markers. In the absence of a conclusive diagnosis, the patient accepted surgery. The biopsy results confirmed diagnosis of striated duct adenoma, with immunohistochemical features superimposable to cytology. CONCLUSION: Little information is available in the literature, both on biopsy and, more strikingly, on cytology of this neoplasm. The aim of this work is to provide cytological characteristics that allow diagnosis of this entity with FNAC and thus avoid unnecessary surgeries.

Papillae, psammoma bodies, and/or many nuclear pseudoinclusions are helpful criteria but should not be required for a definitive cytologic diagnosis of papillary thyroid carcinoma: An institutional experience of 207 cases with surgical follow up.

BACKGROUND: Noninvasive follicular thyroid neoplasm with papillary-like features (NIFTP) was introduced in 2016 replacing noninvasive follicular variant of papillary thyroid carcinoma, with recommendations to label them "noncancer." To avoid reducing risk of malignancy (ROM) and overdiagnosing NIFTP as malignant, some authors required restricted cytologic criteria (RC) for a definitive diagnosis of papillary thyroid carcinoma (PTC), including papillae, psammoma bodies. or ≥3 nuclear pseudoinclusions. Since then, NIFTP criteria have been revised, biologic behavior better understood, and incidence reported to be much lower than initially anticipated. This study examines the impact of RC on PTC cytologic diagnoses, ROM, and detection of clinically significant carcinomas (CSC). MATERIALS AND METHODS: A total of 207 thyroid FNAs originally diagnosed as PTC and suspicious for PTC (SPTC) with surgical follow-up were evaluated. RC were retrospectively applied to cases as a requirement for diagnosing PTC, and cases that did not meet RC were reclassified as SPTC. ROMs and diagnostic accuracies of pre- and post-RC diagnoses were correlated with followup CSC. RESULTS: RC were met in 118/142 (83%) and 20/65 (31%) of cases originally diagnosed as PTC and SPTC, respectively. Post-RC, 29% (19/65) of CSC originally diagnosed as SPTC were upgraded to PTC, and 17% (24/142) of CSC originally diagnosed as PTC were downgraded to SPTC. No NIFTPs were diagnosed as malignant. CONCLUSIONS: RC should not be required for a definitive diagnosis of PTC when other nuclear features of PTC are diffuse and overt. Applying RC, however, helps the pathologist arrive at a more definitive diagnosis of PTC in suspicious cases.

Diagnostic clues for hyalinizing trabecular tumor on fine needle aspiration cytology.

Objectives: The hyalinizing trabecular tumor (HTT) is a rare benign neoplasm of the thyroid gland. This neoplasm has overlapping cytological features with Papillary Thyroid Carcinoma, Medullary Carcinoma and Follicular Neoplasm with Nuclear Features of Papillary Carcinoma. This can lead to misdiagnosis of malignancy in fine needle aspiration (FNA) cytology specimens with unnecessary total thyroidectomy. The aim of this study is to determine if there are some cytological features that could help us to suspect HTT on FNA specimens and avoid radical surgery. Material and Methods: With this purpose we have collected 6 cases diagnosed of HTT in Hospital Clínico San Carlos of Madrid (Spain) in the last 10 years and reviewed the cytological specimens. Result: We conclude that the presence of hyaline material in FNA specimens of HTT is a constant feature being a diagnostic clue. We must be cautious not to confuse it with dense colloid or amyloid material, the latter seen in Medullary Carcinoma. Papillary architecture and fibrovascular cores are not present in a HTT. Special stains as ki-67, calcitonin and Congo Red staining could help us in achieving the correct diagnosis. Conclusion: We feel the cytopathologists must be aware of the distinguishing features of this lesion, mainly the typical hyaline material to achieve a proper diagnosis and be able to reduce unnecessary aggressive management of these patients.

Nuclear CK19-immunopositive pseudoinclusions as a new additional objective diagnostic feature of papillary thyroid carcinoma.

One of the key parameters in the diagnosis of papillary thyroid carcinoma (PTC) are true nuclear pseudoinclusions (NPs), which constitute invaginations of the cytoplasm into the nucleus. On the other hand, strong cytoplasmic expression of CK19 is a well-known attribute of PTC tumor cells. We analyzed NPs using CK19 immunohistochemistry in histological sections of 52 PTCs and seven noninvasive follicular thyroid neoplasms with papillary-like nuclear features (NIFTPs). Strong CK19+ NPs were present in 77% of PTCs, whereas NPs in hematoxylin and eosin (HE)-stained slides (HE NPs) were identified in only 48% of PTCs. Detection of CK19+ NPs enabled easier and objective recognition of NPs and better discrimination of NPs from pseudo-pseudoinclusions than detection of HE NPs. In the 15 of the 27 (55.5%) PTCs in which we could not discern HE NPs, strong CK19+ NPs could be identified reliably, quickly and easily. Moreover, all NIFTPs were negative for both CK19+ NPs and HE NPs. Detection of CK19+ NPs may refine the assessment of this important diagnostic feature and, hence, the microscopic diagnostic criteria of PTC. Thus, these findings may have implications for the accurate diagnosis of PTC and NIFTP.

Ubiquitin Immunostaining in Thyroid Neoplasms Marks True Intranuclear Cytoplasmic Pseudoinclusions and May Help Differentiate Papillary Carcinoma from NIFTP.

Papillary thyroid carcinoma (PTC) is defined by an invasive growth pattern and classic nuclear features: enlarged, grooved, overlapping nuclei with chromatin clearing and intranuclear cytoplasmic pseudoinclusions (INCP). True INCPs are characteristic of PTC, but may infrequently be seen in noninvasive follicular thyroid neoplasms with papillary-like nuclear features (NIFTP). Nuclear abnormalities that mimic INCP ("pseudo-pseudoinclusions") are common in a variety of thyroid lesions. H&E and ubiquitin-stained whole tissue sections of classic PTC (n = 25) and NIFTP (n = 35) were evaluated. On H&E, true INCPs were present in all (100%) PTCs and absent in all NIFTPs (0%). Pseudo-pseudoinclusions were present in 13 (37%) NIFTPs. In 24 (96%) PTCs, ubiquitin was strongly expressed within INCPs. In NIFTPs, optically clear nuclei or pseudo-pseudoinclusions did not express ubiquitin (0/35). Occasionally, nuclear vacuoles in NIFTP demonstrated a marginated staining pattern, in which strong ubiquitin expression was seen at the periphery of the nucleus, but the central pale area was negative. In addition, 2 NIFTPs demonstrated intrafollicular psammomatoid calcifications which were strongly ubiquitin-positive. Psammoma bodies in PTC were ubiquitin-negative in the majority of cases. We report a previously undescribed finding: strong ubiquitin expression in true INCPs in PTC, absence of true INCPs in NIFTP, and absence of ubiquitin expression in pseudo-pseudoinclusions in NIFTP. This finding supports the difference between true INCPs (found only in PTC) and pseudo-pseudoinclusions (found in NIFTP). Using strict histologic criteria and ubiquitin immunostaining, the presence of true pseudoinclusions may exclude a diagnosis of NIFTP. Caution should be exercised when interpreting nuclear vacuoles or pseudo-pseudoinclusions.

Intradermal nevi with atypical nuclei in the elderly: The senescent nevus.

BACKGROUND: Benign melanocytic nevi removed from elderly patients may demonstrate focal areas with nuclear atypia. OBJECTIVE: We sought to determine the prevalence of these nevi and their clinical and histologic features. METHODS: Intradermal nevi from patients older than 60 years were evaluated for areas of focal nuclear atypia and analyzed for 9 histologic characteristics. The patients' sex, biopsy sites, and clinical diagnoses were also tabulated. A statistical analysis of the 2 groups was undertaken. RESULTS: In all, 197 specimens from 157 patients were found. Twenty exhibited nuclear atypia (senescent nevi) and 177 did not (benign nevi). Significant differences were found for suggested clinical diagnosis, epithelioid-appearing melanocytes, the number of mast cells, evidence of solar elastosis, the number of intranuclear pseudoinclusions, and the presence of abnormally staining connective tissue. LIMITATIONS: This is a single-site, retrospective analysis involving a modest number of specimens. In addition, only a single age group was evaluated and only intradermal nevi were examined. CONCLUSIONS: The presence of focal nuclear atypia in benign melanocytic nevi in the elderly is not a rare finding. As these features are likely a result of the age of the lesion and possibly of long-standing ultraviolet light exposure, the term "senescent" nevus is suggested.

Cytological, histological and ultrastructural nuclear features of monster cells in a canine carotid body carcinoma.

A 7-year-old female Shih-tzu dog was presented with severe dyspnoea. A large mass was palpated in the left cranial neck. Cytological examination of an aspirate sample revealed cells with marked anisokaryosis, giant elements and many bare nuclei. Scattered intact giant cells showed scant, granular cytoplasm and intranuclear inclusions. Histologically, neoplastic cells were subdivided into lobules by fine collagenous trabeculae. Numerous pleomorphic giant, or 'monster', cells were observed, showing a highly indented nuclear envelope, intranuclear cytoplasmic pseudoinclusions (ICPs) and 'ground-glass' nuclear appearance. Neoplastic emboli were present, but no distant metastases were detected grossly. Immunohistochemically, the neoplastic cells expressed synaptophysin and had variable expression of neuron-specific enolase and vimentin. The cells were negative for pan-cytokeratin, CAM 5.2, glial fibrillary acidic protein and S100. Nuclear abnormalities and cytoplasmic neurosecretory granules were noted ultrastructurally. These features were consistent with a diagnosis of carotid body carcinoma (chemodectoma). Monster cells with ICPs have not been documented previously in canine chemodectoma.

Chromophobe renal cell carcinoma: a morphologic and immunohistochemical study of 45 cases.

The aim of this study was to evaluate the morphological spectrum of chromophobe renal cell carcinoma (CRCC) and diagnostic utility of a panel of three immunohistochemical stains. All cases of CRCC reported between 2002 and 2012 in the Section of Histopathology, Aga Khan University Hospital, were retrieved. A total of 45 cases were identified. Slides were reviewed and immunohistochemical stains (CK7, CD117, and vimentin) were performed. Ages ranged from 18 to 90 years (mean, 48.5 years). Male-to-female ratio was 0.8:1. The tumor was located in the left kidney in 24 patients and the right kidney in 20 patients. The tumor size ranged from 3.5 to 22 cm (mean 10 cm). Histologically, 4 were classic, 22 were eosinophilic, 16 were mixed, and 3 were sarcomatoid type. Morphologic patterns included broad alveolar, solid, nested, tubular, tubulocystic, trabecular, papillary, and microglandular. Binucleation and perinuclear halos were seen in all cases. Nuclear grooves and pseudoinclusions were seen in 17 and 6 cases, respectively. Multinucleated cells were seen in 19 cases. Mitoses ranged from 1 to 11/10 HPFs (mean 3/10 HPFs). Hyalinized stroma was seen in 38 cases and calcification in 26 cases. Necrosis was seen in 18 cases. Palisading of smaller cells around the broad alveolar pattern was noted in 5 cases. The Furhman's nuclear grade was I (11), II (26), III (5), and IV (3). Hale's colloidal iron was positive in all cases. Immunohistochemical stain CK7 and CD117 were positive in 100% and 95.5% of cases respectively. Vimentin was negative in all cases, except in the sarcomatoid areas of 3 cases. In conclusion, chromophobe renal cell carcinoma has certain unique morphological features and immunohistochemical profile which help to distinguish it from conventional renal cell carcinoma and oncocytoma. We identified nuclear pseudoinclusions, microglandular pattern and palisading of smaller cells, which have not been reported earlier.

Oncocytic adrenocortical carcinoma in a putty-nosed monkey (Cercopithecus nictitans) with hyperadrenocorticism.

Oncocytic adrenocortical tumours are rare in man and have never been described in non-human primates. An oncocytic adrenocortical carcinoma was identified in an 18-year-old female putty-nosed monkey (Cercopithecus nictitans) with hyperadrenocorticism and invasive aspergillosis. Microscopically, the tumour consisted of large cells with abundant eosinophilic, granular cytoplasm containing numerous mitochondria as identified by electron microscopy. Tumour cells had large nuclei with occasional intranuclear cytoplasmic pseudoinclusions. Immunohistochemically, tumour cells expressed vimentin, synaptophysin and neuron-specific enolase, while they were negative for cytokeratin, chromogranin-A, melan-A and S100.