bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mucocele of the Anorectal Pouch: Mucinous Cystic Neoplasm with Low-Grade Dysplasia Simulating Low- Grade Appendiceal Mucinous Neoplasm (LAMN)
Authors: Aydin H B , Faraz M , Qiu H , Lee H , Chismark A D 
Published: November 2023

Abstract

Introduction/Objective
We present the second case of colonic mucocele with dysplasia. To date, only five cases of colonic mucocele have been reported, all in the setting of a pouch or bypass, with only one of them showing dysplasia. The exceptional rarity of the lesion provides unique insight into etiology of mucocele.

Methods/Case Report
A 44-year-old male with complex surgical history including pull-through procedure for imperforate anus at birth, and later proctectomy with end colostomy due to poor anorectal function, presented with worsening low back pain radiating down to his left leg. An abdominal CT scan revealed a large pelvic cyst, causing compressive neuropathy. Multilocular cystic mass (17.5 cm) was resected, which was partially filled with mucinous material. Mucin was not seen on the cyst surface. On microscopic examination, the cyst was largely denuded however was partially lined by markedly attenuated ano-rectal type mucosa and focally by dysplastic glandular epithelium.
Similar to LAMN, pools of acellular mucin dissecting stromal tissues were noted, associated with degenerative changes, calcifications and fibrosis. No invasive carcinoma or high-grade dysplasia was seen. Given the lack of extra- cystic mucin or evidence of overt malignancy, it was reported as mucinous cystic neoplasm with uncertain malignant potential. The patient has been followed for 16 months without evidence of recurrence or peritoneal disease.

Results (if a Case Study enter NA)
NA

Conclusion
Extended stasis within a bowel segment appear to contribute to the development of mucoceles. The blind-ended anatomy of the appendix renders it highly susceptible to this phenomenon, explaining the relatively high incidence of LAMN. Conversely, such prolonged stasis rarely occurs elsewhere in colon unless a pouch or bypassed segment is surgically created, particularly placing patients with a complex surgical history at the highest risk.
Therefore, close follow-up is indicated in this patient group to screen for mucocele that may progress to develop dysplasia and mucinous neoplasm.
Histologic findings in Ogilvie’s syndrome
Authors: Usman A , Sami F I , Lack M , Hamza A 
Published: November 2023

Abstract

Introduction/Objective
Ogilvie Syndrome also known as acute colonic pseudo-obstruction is a rare condition characterized by massive dilation of the colon in the absence of a mechanical obstruction. Leading risk factors include critically ill or hospitalized patients with electrolyte disturbances, in the setting of surgery or trauma. It can be managed conservatively, but if unrecognized and untreated, can lead to life-threatening complications such as ischemic colitis.
The purpose of this report is to describe a case with this complication and its relevant histopathological findings.

Methods/Case Report
A 79-year-old male who had recently undergone radical cystoprostatectomy for urothelial carcinoma presented with significant abdominal distention and unstable vital signs. CT scan showed severe cecal dilation with pneumatosis and portal venous gas concerning for ischemia and perforation. The patient subsequently underwent total colectomy. Grossly, the segment of colon showed areas of mucosal sloughing with a hyperemic and indurated serosal surface.
Microscopically, the sections showed surface erosions, acute inflammatory exudate
(pseudomembranes), attenuated crypts, crypt cytoplasmic mucin loss and vascular congestion, compatible with ischemic changes. In the absence of recent major surgery and critical condition pointing towards Ogilvie's syndrome, these findings can elicit the differential diagnosis of infectious colitis, drug-mediated injury, and inflammatory bowel syndrome.

Results (if a Case Study enter NA)
N/A

Conclusion
This case highlights that Ogilvie’s syndrome can histologically manifest as ischemic colitis and emphasizes that in absence of clinical impression of this syndrome a broader differential diagnosis should be entertained.
Coexistence of Low Grade Appendiceal Mucinous Neoplasm and Endometriosis of the Appendix
Authors: Aryal V , Jum'ah H , Loeffler A , Rayes-Danan R 
Published: November 2023

Abstract

Introduction/Objective
Mucinous neoplasms of the appendix are rare malignancies, and most are found incidentally during surgery and subsequently diagnosed upon pathological examination. The prevalence is about 0.2-0.7%, and approximately one-third (3-34%) are low-grade mucinous neoplasms (LAMNs). Endometriosis is relatively rare in the appendix, accounting for 2.8% with prior history of endometriosis and 0.3% found incidentally in resected specimens. Rare cases of LAMN co-existing with endometriosis have been described in the literature. We report this case of a childbearing age female with the coexistence of LAMN and endometriosis with scarring of the appendix found intraoperatively during the laparoscopic removal of the endometriosis.

Methods/Case Report
A female of childbearing age presents to the hospital with complaints of heavy menses, dysmenorrhea, dyspareunia, and dyschezia during menstruation. The patient has a past medical history of endometriosis. With unsuccessful conservative treatment, the patient was advised to undergo laparoscopic excision of endometriosis. Incidental intraoperative sclerotic small appendix and fibrotic surrounding area was identified, leading to the suspicion of appendicitis likely due to previous recurrent episodes of endometriosis. The surgery was then extended to laparoscopic appendectomy. Histologically, the sections from the appendix showed areas of endometriosis surrounded by endometrial stroma (CD10 positive), also there was atypical glands in the muscularis layer with extra-appendiceal mucin. The glands were lined by cells with elongated nuclei, apical mucin and low-grade nuclear atypia. The patient was diagnosed with low-grade appendiceal neoplasm, extending to the mesoappendix with endometriosis.

Results (if a Case Study enter NA)
N/A

Conclusion
The coexistence of the LAMN and endometriosis is a rare entity. Intestinal metaplasia has been reported in some cases of endometriosis, and this may mimic LAMN. It is important to keep intestinal metaplasia of endometriosis in mind when diagnosing LAMN in an appendix with endometriosis. In our case, the presence of dysplasia, the absence of extensive decidualization, the extracellular mucin helped with the diagnosis.
Uterine Inflammatory Myofibroblastic Tumor with ALK Polysomy: Challenging Case Report and Review of Literature
Authors: Belogrivtseva Y , Yin J , Hennawy R , Taraif S 
Published: November 2023

Abstract

Introduction/Objective
Inflammatory myofibroblastic tumor (IMT) is a distinct neoplastic process with specific molecular alterations. Given its low likelihood of local recurrence and metastasis, it is currently regarded as a neoplasm with intermediate biological potential. IMTs of the uterus variably express CD10 and smooth muscle markers, which present a diagnostic challenge and make it difficult to distinguish from mesenchymal neoplasms of smooth muscle and endometrial stromal origin.

Methods/Case Report
We present a case of a 46-year-old woman who underwent a hysterectomy due to abnormal menstrual bleeding. Grossly, a 5.0 cm tan, firm, well-circumscribed subendometrial nodule was identified at the fundus, which had a fleshy, soft-cut surface with no hemorrhage or necrosis. Microscopically, the nodule is composed of somewhat tightly packed spindle cells arranged in a fascicular pattern, with little-to-no myxoid stroma and dense lymphoplasmacytic infiltrate forming scattered aggregates. Immunohistochemical stains show lesional spindle cells are positive for SMA, desmin, and vimentin with patchy staining for ER while negative for S100, CD10, ALK-1, STAT6, and CD34. CD68 highlights scattered histiocytes in the background. Ki-67 highlights background lymphoid cells. RNA next-generation sequencing detected no fusions involving ROS1, PDGFR-β, or ETV6, which were previously described in a subset of ALK-negative IMTs. The FISH assay did not reveal rearrangements of the ALK or ROS1.
However, extra intact ALK fusion signals were observed, suggesting polysomy for the ALK region.

Results (if a Case Study enter NA)
NA

Conclusion
To our knowledge, this is the first report of a uterine IMT with ALK polysomy. The significance of additional ALK copies in our case is not clear but highlights the need for further molecular studies investigating genetic alterations in ALK-negative IMTs. Detecting these rearrangements may be of diagnostic value and help guide future targeted therapies.
DICER1-Mutant Thyroid Carcinoma of Unusual Morphology: A Follicular Carcinoma with Bizarre Nuclei or a Novel Entity?
Authors: Monroe H , El Naili R 
Published: November 2023

Abstract

Introduction/Objective
DICER1 mutations are associated with a host of benign and malignant neoplasms, of which the thyroid ranks among those with the highest prevalence. We present a case of a DICER1-mutant thyroid carcinoma with unusual morphologic features not described in the existing literature.

Methods/Case Report
A 29-year old 33 weeks pregnant female presented with swelling of the left neck. The patient subsequently underwent an ultrasound, which revealed a thyroid lesion measuring 6.2cm in greatest dimension. Labs including TSH and free T4 wree within normal 3rd trimester limits. Following an unremarkable delivery, FNA revealed loosely clustered cells with marked hyperchromasia and nuclear pleomorphism and variable microfollicular architecture in a colloid-containing background. Though definitively malignant, the anomalous cytomorphology of this neoplasm prompted molecular testing by Afirma Genomic Sequencing Classifier and Xpression Atlas next-generation sequencing, which was significant for a DICER1 hotspot mutation (p.E1705K c.5113G&gt;A).
Follow-up total thyroidectomy was pertinent for a tan-red, nodular mass involving 95% of the thyroid. Histomorphology revealed a neoplasm of primarily macrofollicular architecture with scattered microfollicles and intervening zones that appeared poorly-to-undifferentiated. Cells demonstrated bizarre hyperchromatic, pleomorphic nuclei with multinucleation and Azzopardi effect. Capsular invasion was identified. Inconsistent with a poorly-differentiated or anaplastic carcinoma, the mitotic rate and Ki-67 index were low at &lt; 1/2mm2 and 1-2%, respectively. The tumor was consequently theorized to represent a follicular carcinoma with bizarre nuclei or other entity associated with DICER1 mutations not previously described. To date, no recurrence or metastasis has occurred.

Results (if a Case Study enter NA)
NA

Conclusion
We report an enigmatic morphology of a thyroid cancer associated with a DICER1 mutation. DICER1 mutations have been hitherto described in follicular carcinoma, papillary carcinoma, poorly-differentiated carcinoma and thyroblastoma, none of which are consistent with the present case. Thus, we conjecture that this morphomolecular profile may constitute a "follicular carcinoma with bizarre nuclei" or other novel entity not previously reported. Further investigation should be pursued to determine the nature of this entity, its pathophysiology, epidemiology, possible association with germline DICER1 syndrome, and relationship between morphology and prognosis in patients with DICER1 mutations.
Adenoid Ameloblastoma- A very rare, odontogenic tumor variant with less than 20 reported cases in the literature: Report of two cases and literature review
Authors: Jabbar M , Amer S , Belogrivtseva Y , Lazim A , Proca D , Kuklani R 
Published: November 2023

Abstract

Introduction/Objective
We describe two cases of Adenoid Ameloblastoma (AA), a very rare, hybrid variant, of two of the most common odontogenic neoplasms (Ameloblastoma and adenomatoid odontogenic tumors). AA is a benign epithelial odontogenic tumor characterized microscopically by epithelium resembling conventional ameloblastoma, with additional duct-like structures, epithelial whorls, and cribriform architecture. Dentinoid deposits, clusters of clear cells, and ghost-cell keratinization may also be present. These tumors do not harbor BRAF or KRAS mutations and their molecular basis appears distinct from conventional ameloblastoma but remains unknown. The lesion tends to recur, and sometimes, only correctly diagnosed after recurrence.

Methods/Case Report
Adenoid Ameloblastomas were identified after a review of the Temple University, Department of Pathology archive from 2012-2022. A total of four specimens (two patients) were identified.

Results (if a Case Study enter NA)
Case# 1 22-years-old female
Biopsy
Location/ size: Mandible, left, 2.1 cm.
Microscopic: Neoplastic proliferation composed of odontogenic epithelium in a plexiform pattern with the formation of pseudo glandular structures of variably sized cystic spaces, the peripheral epithelial cells are palisaded with reversed polarity. The central cells have clear cytoplasm and resemble stellate reticulum with occasional tight whorls of cells noted. Hemorrhage and giant cells are present in granulation tissue. The lesion was incompletely excised.
Diagnosis: Benign odontogenic tumor.
Case#2 (1st occurrence):
-49-years-old male
-Biopsy
-Location and size of lesion: Maxilla-left anterior, 0.9 cm.
-Microscopic: Cyst lined by loosely arranged epithelial cells with a basal cell layer having hyperchromatic and palisaded nuclei. Knots of squamous cells are present within the cyst lining. The luminal layer is flattened to cuboidal and nonkeratinized. Duct-like openings are present within the epithelium and contain myxoid stromal tissue. Focally the epithelium extends into the connective tissue as thin anastomosing strands surround the myxoid tissue.
-Diagnosis: Benign odontogenic tumor.
Case#2 (2nd occurrence):
-Biopsy
-Diagnosis: Benign odontogenic tumor
Case#2 (3rd occurrence):
-Excisional biopsy
-Diagnosis: AA

Conclusion
AA is a rare, aggressive odontogenic tumor variant with morphologic overlap with other odontogenic lesions; therefore, oral pathologists and clinicians should be familiar with this entity to achieve an accurate diagnosis and prompt management.
Inflammatory pseudotumor of frontal sinus mimicking an aggressive malignancy: a rare case with diagnostic challenge on fine needle aspiration
Authors: Shaheen M , Saeed O A , Hou T 
Published: November 2023

Abstract

Introduction/Objective
Inflammatory pseudotumor (IPT) of sinonasal tract is a rare disease that sometimes mimicks malignancy in radiographic findings. Diagnosis of IPT on fine needle aspiration (FNA) is challenging due to limited cellularity and lack of architectural evaluation.

Methods/Case Report
Patient is a 59-year-old female presented with left front head swelling, facial pain and pressure. Imaging demonstrated a 3.0 cm hypermetabolic frontal sinus mass with osseous erosion through the calvaria table and deviating the adjacent dura, suspicious for malignancy. Also, an incidental 6.8 cm renal mass was identified and was proven to be clear cell renal cell carcinoma. FNA from frontal sinus showed loosely cohesive atypical cells with prominent nucleoli and occasional mitotic activity mixed with lymphoplasmacytic inflammation and eosinophils. Extensive immunostains showed that the lesional cells were only weakly stained for CD10 and desmin. Because of prominent cytologic atypia and radiological concerning for malignancy, FNA was diagnosed as malignancy not further classified. The patient underwent frontal sinus resection and the surgical specimen showed spindle cell proliferation surrounded by reactive woven bone with plump osteoblasts in a myxocollagenous stroma containing mixed lymphoplasmacytic cells and eosinophils. The spindle cells are positive for actin and calponin, negative for ALK. The spindle cells and plump osteoblasts corresponded to the atypical cells observed on FNA. The overall finding is consistent with IPT, although inflammatory myofibroblastic tumor cannot be completely ruled out. During follow up, the patient developed metastatic renal cell carcinoma in lung. Her frontal sinus lesion was stable for 17 months after surgery.

Results (if a Case Study enter NA)
NA

Conclusion
IPT of sinonasal tract is a rare lesion that sometimes demonstrate aggressive radiologic features. FNA from IPT poses a diagnostic challenge and can be misinterpreted as malignancy due to prominent cytologic atypia. Being aware of this rare entity helps avoid misdiagnosis and triggers the request for core biopsy during onsite evaluation.
Not all hematological malignancies in the gastrointestinal tract are lymphoma
Authors: Cortes P , Patel R , Freeman J 
Published: November 2023

Abstract

Introduction/Objective
Myeloid sarcoma (MS) is a rare entity that may develop in patients with acute myeloid leukemia (AML). Presentation of MS in the gastrointestinal (GI) tract is uncommon. We describe two cases of MS involving unusual sites: the stomach and appendix.

Methods/Case Report
A 64-year-old female consulted for fatigue and abdominal pain. A CT scan of abdomen/pelvis revealed appendicitis and CBC showed 76% blasts. An appendectomy was performed. Histologic examination demonstrated the appendiceal wall infiltrated by malignant cells, ultimately demonstrated to be positive for MPO and weak/variable CD117.
In the second case, a 50-year-old male presented to the emergency department for nausea, vomiting, and elevated amylase. Esophagogastroduodenoscopy with endoscopic ultrasound demonstrated pancreatic inflammatory changes and a subepithelial nodule in the gastric fundus. Biopsy of the nodule revealed gastric epithelium infiltrated by sheets of malignant cells, ultimately demonstrated to be positive for CD34, myeloperoxidase and CD43.

Results (if a Case Study enter NA)
NA

Conclusion
MS is defined as a tumor of myeloid blasts forming outside the bone marrow. Overall, it is an uncommon entity that can occur in patients with known AML, and rarely, as the first sign of AML. Presentation of MS in the GI tract is infrequent (10%), involving primarily the small intestine (63%). The differential diagnosis includes lymphoma, poorly differentiated carcinomas, and melanomas. A review of the clinical history for AML or other myeloproliferative neoplasms should raise suspicion of MS. Expression of lymphoid markers and scant tissue for IHC studies can be diagnostic challenges, rendering B cell lymphoma as the most common misdiagnosis of MS in up to 40-47% of cases. Our two MS cases presented exclusively with GI symptoms without previously known AML and involved unusual GI sites. IHC for myeloid lineage, monocytic or myelomonocytic differentiation should be considered in specific cases. In patients without prior AML diagnosis, especially without hematologic findings, MS is a diagnostic challenge.
EBV positive plasmacytoma in immunocompetent patients: A diagnostically challenging rare entity
Authors: Khan A I , Kataria N , Khan A , Hanan A , Edappallath S , Khattar P , Bedi P 
Published: November 2023

Abstract

Introduction/Objective
Epstein-Barr Virus (EBV)-positive plasmacytoma is a rare entity that shows morphological and immunophenotypic overlap with plasmablastic lymphoma and can cause a diagnostic dilemma. Here we discuss a unique case of EBER-positive plasmacytoma arising from nasal polyps.

Methods/Case Report
A 61-year-old immunocompetent male presented with nasal polyps, right maxillary sinus lesions, and an enlarging sternal lesion. Multiple biopsies were obtained which revealed a diffuse infiltration by atypical plasma cells, that were positive for CD138, MUM1, CD79a, CD56, lambda-in situ hybridization, and Ki67- proliferation index of 20-30%. In situ, hybridization for EBV-encoded viral RNA (EBER) was positive in the neoplastic cells. B- and T- cell markers were negative. The flow cytometry studies detected monotypic lambda-restricted CD38/CD138 positive plasma cells with an aberrant expression of CD56 and CD117. Molecular studies for B-and T- cell gene rearrangement were also negative. A final diagnosis of EBER-positive plasmacytoma was made. The patient was treated with cyclophosphamide, vincristine, doxorubicin, and carboplatin followed by four cycles of RVD, and is doing well.

Results (if a Case Study enter NA)
NA

Conclusion
EBER-positive plasmacytoma poses a diagnostic challenge with plasmablastic lymphoma, specifically in immunocompetent individuals. The useful differentiating clues pointing towards EBER positive plasmacytoma could be a spectrum of morphology ranging from mature to anaplastic, low Ki67 proliferation index, aberrant CD56 and CD117 positivity, and high M- spike on protein studies. Comprehensive clinical, morphologic phenotypic, and genetic investigations are necessary to make a specific diagnosis as the two entities differ in their management.
Epidemiology and Clinical Characteristics of Adult Astrovirus Gastroenteritis in Metropolitan Washington DC, USA: 2016-2023
Authors: Mehdipour Dalivand M , Yee R 
Published: November 2023

Abstract

Introduction/Objective
Astrovirus gastroenteritis is commonly studied in children but not adults. Detection of astrovirus on PCR panels allows for characterization of infected patients. Here, we investigate the epidemiology and clinical characteristics of adult astrovirus infections at our institution.

Methods/Case Report
Stool specimens tested between 01/2016-03/2023 on a gastrointestinal PCR panel (BioFire Diagnostics, Salt Lake City, UT) were analyzed. Chart abstraction was performed to collect patient demographics, laboratory results, clinical presentation and management for patients positive for astrovirus. Fisher Exact Test and 95% Confidence Intervals were calculated where appropriate.

Results (if a Case Study enter NA)
Overall positivity rate of astrovirus was 0.6% (34/5053) with highest (1.02%) in 2018 and none in 2020. The mean age was 32 years old (range:18-52 yo) with majority being Caucasian (56%) and female (56%). Symptoms included diarrhea (100%), abdominal pain (92%), vomiting (47%), and fever (35%).
Comparing patients in age group 30-39 years versus other age groups, vomiting (21% vs 65%, p=0.0173) and fever (40% vs 67%, p=0.717) were less prevalent. More females had abdominal pain (95% vs 87%, p=0.6) while more
males had fever (47% vs 26%, p=0.3) although insignificant. Average period of diarrhea was 3 days (range:1-10 days). 23.5% of patients had increased monocytes (CI 0.29-1.92 x 103/µl), and 29.4% showed decreased lymphocytes (CI 0.29-1.10 x 103/µl). Peak seasons were late winter to spring (February-April). All patients were
immunocompetent except one (HIV+). Gastrointestinal co-infections included toxigenic E. coli (12%), C. difficile (6%), Campylobacter (3%), Norovirus (3%), Salmonella (3%) and Stronglyloides (3%). In all 34 patients, clinicians acknowledged detection of astrovirus and discharged patients without antibiotics.

Conclusion
To our knowledge, this is the first case series on adult astrovirus infections from the D.C. area. We report novel findings about adult astrovirus gastroenteritis that are different from observations in children. PCR can rapidly diagnose viral gastroenteritis and can reduce inappropriate antibiotic administration.