Undifferentiated carcinoma with osteoclast-like giant cells: A pathologic-radiologic correlation of a rare histologic subtype of pancreatic ductal adenocarcinoma.

Undifferentiated carcinoma with osteoclast-like giant cells (UC-OGC) is an exceedingly rare subtype of pancreatic ductal adenocarcinoma. Histologically, UC-OGC is characterized by three cell types namely, a neoplastic mononuclear cell component, non-neoplastic osteoclast-like giant cells, and a non-neoplastic mononuclear histiocytic component. The behavior of this tumor is unpredictable; but many patients survive many years after diagnosis. UC-OGC may have a better prognosis compared to conventional pancreatic adenocarcinoma due to its slower local spread, less aggressive nature, better response to surgical resection and/or chemotherapy, and fewer metastases. Due to likely differences in prognosis and significant impact on patient management, it is important to distinguish this subtype from other types of pancreatic adenocarcinoma. We report a case of a small (<1 cm) undifferentiated carcinoma with osteoclast-like giant cells of the posterior pancreatic body discovered incidentally on magnetic resonance image (MRI) scan of a middle-aged man. The radiologic and pathologic findings are presented along with a discussion of the differential diagnosis of this exceedingly rare entity.

Assessing the value of second opinion pathology review.

BACKGROUND: Second opinion review of pathology cases can identify diagnostic errors that impact patient care. OBJECTIVE: We sought out to determine discrepancy rates and clinical impact of review of pathology cases to reassess our policy of review on all second opinion cases. METHODS: All second opinion pathology cases over 1 year (2018) were retrospectively reviewed for discrepancy, multiple pathologist review and clinicopathologic features via chart and slide review. Cases were categorized as no significant discordance, major discordance without management change and major discordance with management change. RESULTS: Among 4239 second opinion cases, 3.7% (156/4239) had major discordance with no change in management and 1% (42/4239) had major discordance with change in management. Discordance was significantly associated with multiple pathologist review at our institution (P < 0.001). Highest rates of discordance were observed for thyroid fine needle aspiration (15.3%, 26/170), tissue biopsy of bone/soft tissue (9.6%), endocrine (8.8%), genitourinary (6.7%), gynecologic (6.2%), hematopathology (4%), gastrointestinal/liver (3.7%) and thoracic (3%) sites. CONCLUSIONS: Our study showed a 1% major discordance rate with resulting significant change in clinical management, spread across nearly all subspecialties. Thus, we support recommendations for review of relevant outside pathology material for all patients for which review has the potential to illicit management change such as instituting a major medical or surgical therapy.

Correlation of anal cytology with follow-up histology and Human Papillomavirus genotyping: A 10-year experience from an academic medical center.

BACKGROUND: Anal cytology (AC) is accepted as a practical screening modality for anal cancer. However, studies suggest that AC and anal biopsy dysplasia correlation is less robust than in cervicovaginal specimens. The current study goals were to look at our institutional experience in a subset of ACs and correlate with surgical pathology (SP), as well as evaluate their Human Papillomavirus (HPV) status. METHODS: 377 ACs from 169 patients (151 males and 18 females) from 2008 to 2017 were included. HPV genotyping (n = 47) and SP within one year of AC (n = 58) were reviewed. RESULTS: AC/SP was discrepant in 22 cases (37.9%), with a tendency towards AC underestimating the degree of dysplasia. Specifically, any abnormality on AC was 93.8% sensitive for detecting high-grade dysplasia (HGD). However, when requiring a high-grade AC diagnosis, the sensitivity decreases to 12.5%. "Other high-risk HPV" was the most common genotype (57.4%). When considered with all AC with a high-grade diagnosis, co-testing with HPV improved the sensitivity for HGD to 56.3%. Sensitivity improved further to 87.5% when only considering cases with both AC and HPV testing, and were high-risk HPV positive. Furthermore, following review and consensus diagnosis, 8 cases changed from "Discrepant" to "Agreed", reducing the discrepancy rate to 24.1%. Remaining discrepancies were explained by sampling error. CONCLUSION: Given the enhanced sensitivity of AC and HPV testing together, and sampling error seen with AC leading to underestimating dysplasia, we recommend AC and HPV co-testing, as well as describing confounding factors in AC reports and obtaining consensus opinion in equivocal cases.

Fate and Management of Incompletely Excised Solitary Fibrous Tumor of the Orbit: A Case Series and Literature Review.

PURPOSE: There is an imperfect correlation between the histology and behavior of solitary fibrous tumor (SFT). In addition, recurrence is common, and dedifferentiation may occur over time. Preferred primary treatment is intact excision, but friable pseudocapsules and tenacious attachments can thwart this goal in the crowded, visually sensitive orbit. This study addresses the fate and appropriate management of incompletely excised orbital SFT. METHODS: Among a single surgeon's 7-case experience with orbital SFT, 3 cases involved incomplete primary excision, either before (2 cases) or after (1 case) referral. We reviewed the clinicopathologic data in these 3 cases, with follow-up intervals of 18, 21, and 52 years after initial presentation. We reviewed the English-language literature on SFT, with special attention to evolving nomenclature, orbital involvement, recurrence, malignant transformation, and management options. RESULTS: Benign versus malignant designations of SFT vary with histological and behavioral criteria. Approximately 150 orbital cases have been reported. Published rates of primary malignancy and recurrence across all histologic categories are 6% to 12% and 30% to 37%, respectively. We identified 43 well-documented recurrences (range, 6 months-33 years; median, 3 years) and 10 cases of histological dedifferentiation (range, 14 months-33 years). Because of SFT's rarity and needed follow-up intervals, the value of adjuvant therapy is not yet proven. In follow up of 18, 21, and 52 years after initial presentation, our 3 cases with incomplete excision showed either no recurrence (Case 1) or no morphological dedifferentiation (Cases 2, 3). CONCLUSION: A treatment algorithm is predicated on the completeness of surgical excision and histological features. However, we recommend case-by-case multidisciplinary decisions in a tumor-board setting.

Intraductal papillary squamous neoplasm of the pancreas: Cyto-histologic correlation of a novel entity.

We correlate the cytologic and histologic features of a squamous-lined pancreatic cystic lesion with a complex papillary architecture and an associated KRAS mutation, which to our knowledge has not been previously described. A 69 year-old woman presented with intermittent left upper quadrant pain. CT imaging revealed a 1 cm solid lesion in the pancreatic tail with peripheral calcification. Endoscopic ultrasound-guided fine needle biopsy showed a proliferation of epithelial cells with fibrovascular cores. An immunohistochemical stain for p40 was positive in the lesional cells. A distal pancreatectomy revealed a unilocular, cystic, well-circumscribed, soft and friable mass measuring 1.0 × 1.0 × 0.8 cm. Histologically, the cyst was lined by nonkeratinizing stratified squamous epithelium with a complex papillary architecture, filling the cyst lumen. Molecular sequencing revealed a KRAS G12V missense mutation. While the lesion shared some histologic features with the previously described "squamoid cyst of the pancreatic ducts", the complex papillary architecture and presence of a KRAS mutation are unique to the entity we describe herein and we propose the name "intraductal papillary squamous neoplasm of the pancreas." Reporting the cytomorphologic features of this novel entity may help in identification of similar lesions and understanding of the clinicopathologic significance.

Development of primary human pancreatic cancer organoids, matched stromal and immune cells and 3D tumor microenvironment models.

BACKGROUND: Patient-derived tumor models are the new standard for pre-clinical drug testing and biomarker discovery. However, the emerging technology of primary pancreatic cancer organoids has not yet been broadly implemented in research, and complex organotypic models using organoids in co-culture with stromal and immune cellular components of the tumor have yet to be established. In this study, our objective was to develop and characterize pancreatic cancer organoids and multi-cell type organotypic co-culture models to demonstrate their applicability to the study of pancreatic cancer. METHODS: We employed organoid culture methods and flow cytometric, cytologic, immunofluorescent and immunohistochemical methods to develop and characterize patient-derived pancreatic cancer organoids and multi-cell type organotypic co-culture models of the tumor microenvironment. RESULTS: We describe the culture and characterization of human pancreatic cancer organoids from resection, ascites and rapid autopsy sources and the derivation of adherent tumor cell monocultures and tumor-associated fibroblasts from these sources. Primary human organoids displayed tumor-like cellular morphology, tissue architecture and polarity in contrast to cell line spheroids, which formed homogenous, non-lumen forming spheres. Importantly, we demonstrate the construction of complex organotypic models of tumor, stromal and immune components of the tumor microenvironment. Activation of myofibroblast-like cancer associated fibroblasts and tumor-dependent lymphocyte infiltration were observed in these models. CONCLUSIONS: These studies provide the first report of novel and disease-relevant 3D in-vitro models representing pancreatic tumor, stromal and immune components using primary organoid co-cultures representative of the tumor-microenvironment. These models promise to facilitate the study of tumor-stroma and tumor-immune interaction and may be valuable for the assessment of immunotherapeutics such as checkpoint inhibitors in the context of T-cell infiltration.

Low-grade endometrial stromal sarcoma presenting as multiple pulmonary nodules: A potential pitfall in fine needle aspiration and core biopsy specimens - A Cytological - Pathological Correlation.

Low-grade endometrial stromal sarcoma (LGESS) is the second most common malignant mesenchymal tumor of the uterus. The most common location is the uterine corpus, but it can also primarily arise in a variety of extrauterine locations such as pelvis, ovary, abdominal cavity, vagina, and vulva. We are reporting a case of a 47-year-old female with no significant medical history who presented with multiple pulmonary nodules. Fine needle aspiration (FNA) specimen revealed spindle cell neoplasm consistent with the diagnosis of LGESS. The differential diagnosis included neuroendocrine tumor, synovial sarcoma, solitary fibrous tumor, smooth muscle tumors, and peripheral nerve sheath tumors. The clinical, cytological, and histopathologic details of this case, as well as a discussion of the potential pitfalls and differential diagnosis of spindle cell lesions of the lung are described.

Secretory carcinoma of the parotid with adenoid cystic carcinoma cytological pattern: A cytological-pathological correlation with literature review.

Secretory carcinoma (SC) is a rare low-grade malignant tumor, defined by ETV6-NTRK3 fusion, identifiable by FISH. We describe a case in a 58-year-old male with a painless slowly growing 16mm palpable mass within left superficial parotid. FNA of the mass showed highly cellular specimen with moderate to large pleomorphic cells with round to ovoid nuclei with vesicular chromatin and distinct nucleoli. Cells had moderate to large amounts of vacuolated cytoplasm. Abundant globular metachromatic material, resembling that of adenoid cystic carcinoma, was noted. This material was seen extracellularly and intracytoplasmic, and stained magenta on Diff-Quik and blue-green on Papanicolaou-stained slides. The tumor cells on a cell block preparation were positive for Mammaglobin and S-100. PAS stain highlighted extracellular and intracytoplasmic secretions. FNA diagnosis was "Positive for Malignancy. Morphologic features most compatible with Mammary Analogue Secretory Carcinoma". ETV6 FISH studies as well as histologic examination of excised tumor confirmed the diagnosis. Finding the globular metachromatic material in SC, that is generally seen in adenoid cystic carcinoma, broadens a cytological differential diagnosis of both entities. Cytological differential diagnosis, clinical, histological, immunohistochemical, and molecular features of secretory carcinomas are discussed in this study.

Oncocytic Adenocarcinoma of the Orbit.

Oncocytic adenocarcinoma of the orbit is a rare tumor, with 1 case of nonlacrimal sac, nonlacrimal gland origin, and a poor outcome previously reported. An 85-year-old man with a 2-month history of left-sided epiphora, enlarging eyelid nodules, and diplopia in left gaze was found on imaging to have a poorly circumscribed, nodular mass of uniform radiodensity in the inferomedial orbit. Incisional biopsy revealed morphologic and immunohistochemical features of oncocytic adenocarcinoma with origin in the caruncle suspected, and CT of the neck, chest, abdomen, and pelvis showed no metastases or remote primary tumor source. Based on multidisciplinary consensus, orbital exenteration with adjuvant radiation therapy was performed, and there was no evidence of residual or recurrent tumor 2 years after treatment.

Eliminating the Residual Negative Pressure in the Endoscopic Ultrasound Aspirating Needle Enhances Cytology Yield of Pancreas Masses.

BACKGROUND: Prior to withdrawing the EUS-FNA needle from the lesion, the stopcock of the suction syringe is closed to reduce contamination. Residual negative pressure (RNP) may persist in the needle despite closing the stopcock. AIMS: To determine whether neutralizing RNP before withdrawing the needle will improve the cytology yield. METHODS: Bench-top testing was done to confirm the presence of RNP followed by a prospective, randomized, cross-over study on patients with pancreas mass. Ten milliliters of suction was applied to the FNA needle. Before withdrawing the needle from the lesion, the stopcock was closed. Based on randomization, the first pass was done with the stopcock either attached to the needle (S+) or disconnected (S-) to allow air to enter and neutralize RNP and accordingly the second pass was crossed over to S+ or S-. On-site cytopathologist was blinded to S+/S-. RESULTS: Bench tests confirmed the presence of RNP which was successfully neutralized by disconnecting the syringe (S-) from the needle. Sixty patients were enrolled, 120 samples analyzed. S+ samples showed significantly greater GI tract contamination compared to S- samples (16.7 vs. 6.7%, p = 0.03). Of the 53 patients confirmed to have pancreas adenocarcinoma, FNA using S- approach was positive in 49 (93%) compared to 40 using the S+ approach (76%, p = 0.02). CONCLUSIONS: Despite closing the stopcock of the suction syringe, RNP is present in the FNA needle. Neutralizing RNP prior to withdrawing the needle from the target lesion significantly decreased GI tract contamination of the sample thereby improving the FNA cytology yield. CLINICAL TRIALS REGISTRATION NUMBER: NCT01995474.

Rectovaginal endometriosis with nodular smooth muscle metaplasia diagnosed via transrectal ultrasound-guided fine-needle aspiration cytology: An underused minimally invasive diagnostic technique?

Rectovaginal endometriosis is a severe variant of deeply infiltrating endometriosis. Laparoscopic assessment with tissue sampling remains the gold standard for diagnosis of endometriosis. However, transvaginal (TVUS) and transrectal ultrasound (TRUS) have been shown to be especially helpful in the diagnosis of deep endometriosis. We present the case of a 49-year-old female with menorrhagia, dysmenorrhea, and constipation. Upon pelvic examination, an incidental mass was palpated. A computed tomography (CT) scan revealed an anterior rectal wall mass and colonoscopy was non-diagnostic. Further work-up with MRI showed a 3.9 cm mass centered within the upper rectovaginal septum. TRUS guided fine-needle aspiration (TRUS-FNA) revealed cohesive epithelial cell groups without significant cytologic atypia and a second population of bland spindle cells. Cell block slides showed glandular epithelium with associated stroma that exhibited endometrial morphology and immunophenotype. Nodular fragments of spindle cells with smooth muscle immunophenotype and fibrosis were also present. The overall morphologic findings were consistent with rectovaginal endometriosis with nodular smooth muscle metaplasia. Medical management with nonsteroidal aromatase inhibitor with radiologic follow-up was selected. Rectovaginal endometriosis represents a type of deep endometriosis usually associated with severe pelvic symptoms. Metaplastic smooth muscle cells are a frequent component of endometriosis in the rectovaginal pouch with nodular growth and may present diagnostic challenges. TRUS-FNA is a minimally invasive procedure that can provide an accurate diagnosis of endometriosis, even in this variant of deep infiltrating disease.

Collagen-Specific HSP47+ Myofibroblasts and CD163+ Macrophages Identify Profibrotic Phenotypes in Deceased Hearts With SARS-CoV-2 Infections.

Background Cardiac fibrosis complicates SARS-CoV-2 infections and has been linked to arrhythmic complications in survivors. Accordingly, we sought evidence of increased HSP47 (heat shock protein 47), a stress-inducible chaperone protein that regulates biosynthesis and secretion of procollagen in heart tissue, with the goal of elucidating molecular mechanisms underlying cardiac fibrosis in subjects with this viral infection. Methods and Results Using human autopsy tissue, immunofluorescence, and immunohistochemistry, we quantified Hsp47+ cells and collagen α 1(l) in hearts from people with SARS-CoV-2 infections. Because macrophages are also linked to inflammation, we measured CD163+ cells in the same tissues. We observed irregular groups of spindle-shaped HSP47+ and CD163+ cells as well as increased collagen α 1(I) deposition, each proximate to one another in "hot spots" of ≈40% of hearts after SARS-CoV-2 infection (HSP47+ P<0.05 versus nonfibrotics and P<0.001 versus controls). Because HSP47+ cells are consistent with myofibroblasts, subjects with hot spots are termed "profibrotic." The remaining 60% of subjects dying with COVID-19 without hot spots are referred to as "nonfibrotic." No control subject exhibited hot spots. Conclusions Colocalization of myofibroblasts, M2(CD163+) macrophages, and collagen α 1(l) may be the first evidence of a COVID-19-related "profibrotic phenotype" in human hearts in situ. The potential public health and diagnostic implications of these observations require follow-up to further define mechanisms of viral-mediated cardiac fibrosis.

Dysphagia due to adenoid cystic carcinoma of the base of the tongue.

OBJECTIVES: Although oropharyngeal neoplasia can often lead to dysphagia, salivary gland tumors rarely grow within the tongue base. We present the case of a 75-year-old man with adenoid cystic carcinoma of the base of the tongue causing profound dysphagia and weight loss, and provide a current literature review and update on the management of these rare tumors. METHODS: We present a case report and a literature review. RESULTS: Physical examination performed at the initial visit revealed a firm right base-of-tongue mass with no palpable lymphadenopathy. Flexible fiberoptic laryngoscopy confirmed a large submucosal mass at the right base of the tongue that obscured the right vallecula. Histopathologic analysis of the operative biopsy specimens revealed the classic features of adenoid cystic carcinoma. Treatment included radical pharyngotomy with wide local excision and primary closure, followed by postoperative radiation treatment. CONCLUSIONS: We demonstrate the clinical examination findings and histopathologic characteristics of this disease, and review the literature for clinical treatment recommendations for this rare cause of dysphagia.

Fine-needle aspiration diagnosis of clonal extramedullary hematopoiesis in a case of myeloproliferative neoplasm.

Extramedullary hematopoiesis (EMH)-the proliferation of hematopoietic progenitors outside of the bone marrow (BM) is a well-known phenomenon in myeloproliferative neoplasms (MPN). Abundant literature describes EMH at various body sites in cases of MPN, and some studies showed the presence of cytogenetic changes associated with MPN in the EMH tissues. We present a case of an 80-year-old female, with a history of MPN, presenting with mediastinal adenopathy. The transbronchial fine-needle aspiration (FNA) of the mediastinal lymph node showed EMH with atypical megakaryocytes and del(13q) demonstrated by fluorescence in situ hybridization. The subsequent BM biopsy demonstrated myelofibrosis with atypical megakaryocytes harboring the same cytogenetic abnormality. Our case highlights the capability of FNA cytology for providing accurate morphologic, immunohistochemical, and cytogenetic diagnosis of clonal EMH.

Assessment of Quality of Frozen Section Services at a Large Academic Hospital Before and After Relocation.

OBJECTIVES: To determine outcomes following relocation of frozen section services (FSS) and the implementation of a dedicated gastrointestinal frozen service. METHODS: We reviewed our FSS 6 months prior to and following FSS relocation. Satisfaction surveys were sent to surgeons and pathologists. Survey feedback resulted in a pilot of gastrointestinal subspecialist frozen section coverage. RESULTS: There were 1,607 and 1,472 specimens from 667 and 602 patients pre- and post-FSS relocation, respectively. There was a decline in median specimen delivery time to pathology (12 vs 10 minutes, P < .001) and an increase in median time from receipt in pathology to intraoperative diagnosis (20 vs 22 minutes, P = .008) in cases with intrapathology consultation but no change without consultation (median, 19 minutes). Intrapathology consultation decreased from 19.7% (317/1,607) to 11.5% (169/1,472) (P < .001). Discordance rates between frozen section and permanent section remained low and similar (2.0% [33/1,607] vs 2.7% [40/1,472], P = .24). There was no significant change in discordance with dedicated gastrointestinal subspecialty frozen section interpretation. CONCLUSIONS: Relocation of FSS and dedicated subspecialty interpretation may improve surgeon satisfaction but can also create workflow challenges. Pathology departments need to achieve a balance between satisfaction and adequacy to establish best frozen section coverage models.

p16 immunocytochemistry on cell blocks as an adjunct to cervical cytology: Potential reflex testing on specially prepared cell blocks from residual liquid-based cytology specimens.

BACKGROUND: p16 (INK4a) (p16) is a well-recognized surrogate molecular marker for human papilloma virus (HPV) related squamous dysplasia. Our hypothesis is that the invasive interventions and related morbidities could be avoided by objective stratification of positive cytologic interpretations by p16 immunostaining of cell block sections of cytology specimens. MATERIALS AND METHODS: Nuclear immunoreactivity for p16 was evaluated in cell block sections in 133 adequate cases [20 negative for intraepithelial lesion or malignancy, 28 high-grade squamous intraepithelial lesion (HSIL), 50 low-grade squamous intraepithelial lesion (LSIL), 21 atypical squamous cells, cannot exclude HSIL (ASC-H), and 14 atypical squamous cells of undetermined significance (ASCUS)] and analyzed with cervical biopsy results. RESULTS: (a) HSIL cytology (28): 21 (75%) were p16 positive (11 biopsies available - 92% were positive for cervical intraepithelial neoplasia (CIN) 1 and above) and 7 (25%) were p16 negative (3 biopsies available - all showed only HPV with small atypical parakeratotic cells). (b) LSIL cytology (50): 13 (26%) cases were p16 positive (12 biopsies available - all were CIN1 or above) and 37 (74%) were p16 negative (12 biopsies available - all negative for dysplasia. However, 9 (75%) of these biopsies showed HPV). (c) ASC-H cytology (21): 14 (67%) were p16 positive (6 biopsies available - 5 showed CIN 3/Carcinoma in situ/Ca and 1 showed CIN 1 with possibility of under-sampling. Cytomorphologic re-review favored HSIL) and 7 (33%) were p16 negative (5 biopsies available - 3 negative for dysplasia. Remaining 2 cases - 1 positive for CIN 3 and 1 showed CIN 1 with scant ASC-H cells on cytomorphologic re-review with possibility under-sampling in cytology specimen). (d) ASCUS cytology (14): All (100%) were p16 negative on cell block sections of cervical cytology specimen. HPV testing performed in last 6 months in 7 cases was positive in 3 (43%) cases. CONCLUSION: p16 immunostaining on cell block sections of cervical cytology specimens showed distinct correlation patterns with biopsy results. Reflex p16 immunostaining of cell blocks based on the algorithmic approach to be evaluated by a multiinstitutional comprehensive prospective study is proposed.

Cystic Lesions of the Pancreas: Differential Diagnosis and Cytologic-Histologic Correlation.

CONTEXT.­: Pancreatic cystic lesions (PCLs) are very common, and their detection is increasing with the advances in imaging techniques. Because of the major implications for management, distinguishing between neoplastic and nonneoplastic PCLs is critical. Neoplastic cysts with potential to progress into cancer include mucinous PCLs (intraductal papillary mucinous neoplasms and mucinous cystic neoplasms) and nonmucinous cysts (solid pseudopapillary tumors, serous cystic neoplasms, and neuroendocrine tumors with cystic degeneration). Nonneoplastic cysts with no risk of malignant transformation include pseudocysts, retention cysts, lymphoepithelial cysts, cystic pancreatic lymphangioma, and duplication cyst/ciliated foregut cysts. The role of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) cytology with cyst fluid analysis in the diagnosis of PCLs has evolved during the last decade; however, a definitive diagnosis on cytologic specimens is hampered by the sparse cellularity and can be challenging. EUS-FNA can play an important role to differentiate low-risk from high-risk pancreatic cysts and to distinguish between patients with cysts who need clinical follow-up versus those who require surgery. OBJECTIVE.­: To provide an integrative approach to diagnose pancreatic cystic lesions using EUS-FNA cytology and cyst fluid analysis, along with clinical, radiologic, histologic, genetic, and molecular characteristics. DATA SOURCES.­: The review and analysis of the latest literature describing pancreatic cystic lesions. CONCLUSIONS.­: Accurate diagnosis of PCLs requires a multidisciplinary and multimodal team approach, including the integration of clinical findings, imaging, cytology, cyst fluid analysis, and molecular testing.

VANISHING PAPILLARY THYROID CARCINOMA: MORPHOLOGICAL CHANGES AFTER FINE-NEEDLE ASPIRATION.

OBJECTIVE: Fine-needle aspiration (FNA) of a thyroid nodule is typically considered a benign procedure. Uncommonly, morphological changes can occur in the nodule or tissue after the procedure. These changes have been noted in tissues like thyroid, breast, lymph node, and prostate. The objective of this case report is to report the rare occurrence of thyroid cancer diagnosed on FNA, appearing as a necrotic mass after near total thyroidectomy and to emphasize the need for confirmation of diagnosis with histopathology. METHODS: A 69-year-old man was seen for a self-discovered neck mass. Thyroid ultrasound demonstrated a thyroid nodule with suspicious features. Ultrasound-guided FNA of the nodule was performed with a 22-gauge needle without immediate complications. RESULTS: The cytology was read as consistent with papillary thyroid cancer with a preoperative thyroglobulin level of 15,288 ng/mL (normal range is 1.6-55 ng/mL). After a near total thyroidectomy, histopathology revealed complete infarction of the tumor with no evidence of cancerous tissue remaining. Based on the pathology report, he was considered cured of the cancer and did not receive radioactive iodine therapy. CONCLUSION: The occurrence of tissue infarction following FNA of a thyroid nodule is rare, reportedly <2%. We conclude a review of the original cytology material and a thorough examination of remaining viable tissue be made. Complete evaluation for invasion of the capsule or surrounding tissue must be ascertained to decrease diagnostic errors.

Papillary Carcinoma of Stensen's Duct with Intestinal Differentiation.

Stensen's duct carcinoma (StDC) is an extremely rare neoplasm, with fewer than 40 cases reported in the literature. We report a unique case of primary StDC with papillary features and intestinal differentiation of a 74-year-old male. We discuss the radiologic and pathologic correlation along with the differential diagnosis of this rare entity.