Ghost Cell Odontogenic Carcinoma Arising in a Previous Calcifying Odontogenic Cyst: A Case Report and Review of Literature.

Ghost cell odontogenic carcinoma (GCOC) is a rare malignant tumor of odontogenic origin, with only about 50 cases reported in the English literature so far. Histologically, it is characterized by ghost cells, dentinoid deposits, high grade malignant cellular features, and areas of necrosis and invasion. Having common histological features with other odontogenic ghost cell lesions (OGCL) like calcifying odontogenic cyst (COC) and dentinogenic ghost cell tumors, it is crucial to recognize GCOC malignant features, as it can be destructive and invasive, sometimes showing distant metastases and high recurrence rate. For this reason, it may entail more aggressive surgical approach and multimodal therapeutic regimen. Here we present a case report of GCOC arising in a previous COC, treated with surgical excision that showed persistence and recurrence after two years. The clinical and histological features of this rare occurrence are presented, in addition to the surgical approach, and a summary of literature review of OGCL.

Gastrointestinal Tract Injury by Yttrium-90 Appears Largely Restricted to Resin Microspheres But Can Occur Years After Embolization.

Radioembolization therapy utilizes yttrium-90 (Y90) impregnated resin (SIR-Spheres) or glass (TheraSpheres) microspheres to selectively target hepatic lesions via transarterial radioembolization. Occasional cases of gastrointestinal tract injury, secondary to nontargeted delivery of microspheres, have been reported, but large descriptive pathology series are lacking. We identified 20 cases of histologically confirmed mucosal injury associated with Y90 from 17 patients and assessed the corresponding clinical and pathologic sequelae. The mucosal biopsies were obtained from 1 to 88 months following Y90 therapy (median: 5 mo). Most cases were gastric (17, 85%), while the remaining were duodenal. Endoscopic ulceration was seen in the majority of cases (16, 80%), and mucosal erythema in the remaining 4. Histologically, a majority (19, 95%) of cases showed rounded, dark blue to purple microspheres measuring 4 to 30 µm, consistent with resin microspheres. A single case with glass microspheres demonstrated 26 µm translucent beads. Histologic evidence of ulceration was appreciated in 14 (70%) cases, and the microspheres were clearly intravascular in 6 (30%). A foreign body giant cell reaction to the microspheres was uncommon (3 cases, 15%). We additionally performed a retrospective review of all gastrointestinal tissue obtained postprocedure from 784 sequential patients treated with Y90 microspheres. Three patients (0.4%) demonstrated the presence of resin microspheres upon histologic examination. No cases involving glass-based Y90 were identified ( P =0.0078), despite the majority of patients having received glass radioembolization (630, 80%). This increased risk of secondary sphere dissemination is likely related to the increased number of particles required per activity for resin versus glass microspheres. We conclude that Y90 microspheres may be encountered in the gastrointestinal tract years after initial liver-targeted therapy and, when present, are often associated with mucosal ulceration. This finding is less likely to be encountered in patients who received Y90 radioembolization utilizing glass microspheres.

Predictors of Recurrence and Survival in Patients With Surgically Resected Pancreatic Neuroendocrine Tumors.

OBJECTIVE: Given the lack of consensus on surveillance guidelines after pancreatic neuroendocrine tumor (PanNET) resection, we assessed outcomes in a large cohort of patients with nonmetastatic, surgically resected PanNETs. METHODS: Data of patients with PanNETs resected between 1990 and 2017 were retrospectively collected using databases at 3 academic institutions. The National Death Index was queried to determine vital status. Kaplan-Meier analysis was used to estimate recurrence-free survival (RFS) and disease-specific survival (DSS) rates. Variables associated with recurrence and disease-related death were identified through Cox multivariate analyses. RESULTS: Of 307 patients with PanNET who underwent resection, recurrence occurred in 79 (26%) of patients. For stage I and II disease, 5-year RFS rates were 90% and 43%, whereas 5-year DSS rates were 98% and 86% (P < 0.0001 and P = 0.0038, respectively). For grades 1, 2, and 3 disease, 5-year RFS rates were 87%, 49%, and 18%, and 5-year DSS rates were 98%, 89%, and 51% (P < 0.0001 for both). Stage II, grade 2, and grade 3 disease were each associated with increased recurrence and disease-specific death. CONCLUSIONS: Stage and grade are important prognostic factors that should be utilized to tailor postsurgical surveillance after curative resection of PanNET.

Grade is a Dominant Risk Factor for Metastasis in Patients with Rectal Neuroendocrine Tumors.

BACKGROUND: Small (< 2 cm) and diminutive (< 1 cm) rectal neuroendocrine tumors (RNETs) are often described as indolent lesions. A large single-center experience was reviewed to determine the incidence of metastasis and the risk factors for its occurrence. METHODS: Cases of RNET between 2010 and 2017 at a single institution were retrospectively reviewed. The rate of metastasis was determined, and outcomes were stratified by tumor size and grade. Uni- and multivariable predictors of metastasis were identified, and a classification and regression tree analysis was used to stratify the risk for distant metastasis. RESULTS: The study identified 98 patients with RNET. The median follow-up period was 28 months. Of the 98 patients, 79 had primary tumors smaller than 1 cm, 8 had tumors 1 to 2 cm in size, and 11 had tumors 2 cm in size or larger. In terms of grade, 86 patients had grade 1 (G1) tumors, 8 patients had grade 2 (G2) tumors, and 4 patients had grade 3 (G3) tumors. Twelve patients developed metastatic disease. Both size and grade were associated with distant metastasis in the uni- and multivariable analyses, but when stratified by grade, size was predictive of metastasis only for G1 tumors (p < 0.001). Among the 12 patients with metastatic disease, 3 (25%) had diminutive primary tumors, and 9 (75%) had primary tumors 2 cm in size or larger. Diminutive tumors that metastasized were all G2. CONCLUSIONS: Patients with diminutive and small RNETs are at risk for metastatic disease. Tumor grade is a dominant predictor of dissemination. More rigorous staging, closer surveillance, or more aggressive initial management may be warranted for patients with G2 tumors, irrespective of size.

Clusterin in Neuroendocrine Epithelial Neoplasms: Absence of Expression in a Well-differentiated Tumor Suggests a Jejunoileal Origin.

Clusterin, a widely expressed, tissue-specific glycoprotein, is a diagnostic marker of several tumor types, including anaplastic large cell lymphoma, follicular dendritic cell sarcoma, and tenosynovial giant cell tumor. A recent study has suggested it is highly expressed by well-differentiated neuroendocrine tumors (NET) arising at most anatomic sites, with the exception of jejunoileal tumors, and that it is similarly not expressed by poorly differentiated neuroendocrine carcinomas (NEC). We sought to validate this result in a large cohort of NETs and NECs. Clusterin immunohistochemistry was performed on tissue microarrays of 255 NETs [45 lung, 4 stomach, 8 duodenum, 75 pancreas (62 primary, 13 metastatic), 107 jejunoileum (69 primary, 38 metastatic), 16 appendix] and 88 NECs (43 visceral, 45 Merkel cell). Extent (%) and intensity (0, 1+, 2+, 3+) of staining were assessed and an H-score (extent x intensity) calculated. An average H-score >5 was considered positive. Clusterin expression was noted in 82.4% of 148 nonjejunoileal NETs (average H-score 183) and only 8.4% of 107 jejunoileal NETs (average H-score, 31), as well as 19.3% of NECs (average H-score, 36). Clusterin is frequently, strongly expressed by NETs of diverse anatomic sites, with the exception of jejunoileal tumors, in which it is only rarely, weakly expressed. It is occasionally, weakly expressed by NECs. Most metastatic NETs of occult origin arise in the pancreas or the jejunoileum. For cases in which an initial site of origin immunopanel (eg, islet 1, PAX6, CDX2) is ambiguous, addition of clusterin may be diagnostically useful, with absence of expression suggesting a jejunoileal origin.

A practical method to determine the site of unknown primary in metastatic neuroendocrine tumors.

INTRODUCTION: The site of a primary neuroendocrine tumor (NET) tumor is unknown before treatment in approximately 20% of small bowel (SBNET) and pancreatic (PNET) cases despite extensive workup. It can be difficult to discern a PNET from an SBNET on hematoxylin and eosin stains, and thus, more focused diagnostic tests are required. Immunohistochemistry (IHC) and gene expression profiling are two methods used to identify the tissue of origin from biopsied metastases. METHODS: Tissue microarrays were created from operative specimens and stained with up to seven antibodies used in the NET-specific IHC algorithm. Expression of four genes for differentiating between PNETs and SBNETs was determined by quantitative polymerase chain reaction and then used in a previously validated gene expression classifier (GEC) algorithm designed to determine the primary site from gastrointestinal NET metastases. RESULTS: The accuracy of the IHC algorithm in identifying the primary tumor site from a set of 37 metastases was 89%, with only one incorrect call. Three other samples were indeterminate as the result of pan-negative staining. The GEC's accuracy in a set of 136 metastases was 94%. The algorithm identified the primary tumor site in all cases in which IHC failed. CONCLUSION: Performing IHC, followed by GEC for indeterminate cases, identifies accurately the primary site in SBNET and PNET metastases in virtually all patients.