MiNEN of base of tongue - first case report in literature.

INTRODUCTION: Mixed neuroendocrine and non-neuroendocrine neoplasms (MiNENs) refer to a heterogenous group of rare neoplasms which is usually composed of a neuroendocrine population which is either well differentiated and more frequently poorly differentiated along with a non-neuroendocrine component, each of the above accounting for at least 30% of the tumour population. It is most commonly seen in the gastro-entero-pancreatic tract. MiNENs have an aggressive behaviour due to its high grade neuroendocrine component and have poor prognosis. This is the first case reported in literature of a MiNEN in the oropharynx. CASE REPORT: 69 year old male patient with no co morbidities presented to the outpatient department with complains of odynophagia for 1 month. He had history of neoadjuvant chemotherapy followed by transoral robotic surgery (TORS) with right selective neck dissection (SND) done in 2019 for carcinoma base of tongue. On flexible laryngoscopy, an ulcerative lesion was noted over the left base of tongue. Although PET scan done showed no significant abnormalities. Biopsy from the lesion showed features of poorly differentiated carcinoma along with morphological features of poorly differentiated neuroendocrine carcinoma (small cell carcinoma). He was planned for upfront surgery (TORS with left SND). Post operatively recovery was uneventful and patient was on ryles tube feed for 12 days. Final histopathology report showed features of mixed neuroendocrine non neuroendocrine neoplasm. He has been on follow up for 1 year with no features of recurrence. CONCLUSION: MiNEN is an aggressive tumour which has poor prognosis and is most commonly located in the gastrointestinal tract. This is the first case reported in oropharynx who has been successfully treated and has been on follow up.

Goblet cell adenocarcinoma.

Appendix, considered a vestigial and disposable organ, has been long neglected as a source of abdominal tumors. Among the appendiceal tumors, goblet cell adenocarcinoma (GCA) is a rare primary epithelial neoplasm which has undergone multiple name changes and classifications in recent years, adding to confusion surrounding this unique amphicrine tumor. This entity was previously known as goblet cell carcinoid and adenocarcinoma ex goblet cell carcinoid. This review article provides an update on pathology, nomenclature, and recent classification systems with emphasis on 2019 World Health Organization Classification of Tumors, 3-tiered grading system.1.

Does the size of the neuroendocrine-carcinoma component determine the prognosis of gallbladder cancer?

Background: Gallbladder mixed neuroendocrine-non-neuroendocrine neoplasm generally consists of a gallbladder neuroendocrine tumor and a non-neuroendocrine component. The World Health Organization (WHO) in 2019 established a guideline requiring each component, both neuroendocrine and non-neuroendocrine, to account for a minimum of 30% of the tumor mass. Methods: Patients after surgery resection and diagnosed at microscopy evaluation with pure gallbladder neuroendocrine carcinoma (GBNEC), gallbladder mixed adeno-neuroendocrine carcinoma (GBMANEC, GBNEC≥30%), and gallbladder carcinoma mixed with a small fraction of GBNEC (GBNEC <30%) between 2010 and 2022 at West China Hospital of Sichuan University were collated for the analyses. Demographic features, surgical variables, and tumor characteristics were evaluated for association with patients' overall and recurrence-free survival (OS and RFS). Results: The study included 26 GBNEC, 11 GBMANEC, 4 gallbladder squamous-cell carcinoma (GBSCC), and 7 gallbladder adenocarcinoma (GBADC) mixed with a small fraction of GBNEC. All patients had stage III or higher tumors (AJCC8th edition). The majority of included patients (79.17%) underwent curative surgical resection (R0), with only ten patients having tumoral resection margins. In the analysis comparing patients with GBNEC percentage (GBNEC≥30% vs. GBNEC<30%), the basic demographics and tumor characteristics of most patients were comparable. The prognosis of these patients was also comparable, with a median OS of 23.65 months versus 20.40 months (P=0.13) and a median RFS of 17.1 months versus 12.3 months (P=0.24). However, patients with GBADC or GBSCC mixed with GBNEC <30% had a statistically significant decreased OS and RFS (both P<0.0001)) compared with GBNEC and GBMANEC. Patients with GBNEC who exhibited advanced tumor stages and lymphovascular invasion had a higher risk of experiencing worse overall survival (OS) and recurrence-free survival (RFS). However, a 30% GBNEC component was not identified as an independent risk factor. Conclusion: Patients with GBNEC were frequently diagnosed at advanced stages and their prognosis is poor. The 30% percentage of the GBNEC component is not related to the patient's survival.

Distinctive Phenotypic and Microenvironmental Characteristics of Neuroendocrine Carcinoma and Adenocarcinoma Components in Gastric Mixed Adenoneuroendocrine Carcinoma.

This study aimed to conduct an in-depth examination of gene expression and microenvironmental profiles of gastric neuroendocrine carcinoma (NEC) and mixed adeno-NEC (MANEC). Tissue microarrays from 55 patients with gastric MANEC (N = 32) or NEC (N = 23) were analyzed using digital spatial profiling (GeoMx DSP, NanoString Technologies). Representative regions of interest were selected from the adenocarcinoma (ADC) portion (ADC-MANEC) and the NEC portion (NEC-MANEC) of the MANEC cores, and pure NEC (pNEC) cores. All regions of interest were separated into epithelial components and stromal components using the masking procedure in the GeoMx platform, followed by transcriptome analysis. Comparison of gene expression between ADC-MANEC and NEC-MANEC/pNEC identified several differentially expressed genes in the epithelial (including PEG10, MAP1B, STMN3, and AKT3) and stromal (FN1, COL1A1, SPARC, and BGN) components. Gene set enrichment analysis revealed that pathways related to the E2F target and G2M checkpoint were more enriched in NEC-MANEC and pNEC than in ADC-MANEC. Deconvolution analysis showed that the microenvironmental profile varied according to histologic differentiation. In ADC-MANEC, intraepithelial infiltrating immune cells were relatively more numerous, whereas fibroblasts in the stroma were more abundant in NEC-MANEC and pNEC. This study confirmed the distinct expression profile of each histologic component of MANEC according to its tumor vs stromal compartment using the DSP platform. Although each component of MANEC shares the same genetic origin, distinctive phenotypes should not be overlooked when managing patients with MANEC. This study provides a useful validation data set for future studies.

Retroperitoneal mixed neuroendocrine non-neuroendocrine neoplasm: A case report and review of literature.

The existence of both neuroendocrine and non-neuroendocrine histology in variable proportion in a lesion has been described by the World Health Organisation (WHO) as mixed neuroendocrine and non-neuroendocrine neoplasm (MiNEN). The pathogenesis of this tumour remains controversial but molecular studies point towards a common monoclonal origin. Tumours are classified as functioning and nonfunctioning based on substances secreted. The nonfunctioning tumours may be discovered due to its local effect. Presented is a 66-year-old male with an intra-abdominal mass, underwent laparotomy and excision biopsy with transient right lower limb lymphoedema. Histology confirmed retroperitoneal MiNEN with no evidence of tumour recurrence 12 months following surgery. MiNENs should be considered as a differential diagnosis in patients with intra-abdominal mass. Surgical resection is recommended as this may offer the best treatment option.

[Mixed adenoneuroendocrine carcinoma: case report]. / Carcinoma adenoneuroendocrino mixto: reporte de caso.

Introducción: Mixed adenoneuroendocrine carcinoma is a rare tumor of the gastrointestinal tract with double differentiation into adenomatous and neuroendocrine carcinoma, each component with at least 30%. Case report: A 60-year-old female with acute abdominal pain. Surgical treatment was decided, finding a tumor at the level of the cecum and ascending colon, a right hemicolectomy and ileostomy were performed. Discussion: Mixed adenoneuroendocrine carcinoma can appear in various organs. They are highly malignant tumors, with a high risk of metastasis. Conclusions: These tumors do not present symptoms or specific radiological or laboratory findings; diagnosis depends on postoperative histopathological and immunohistochemical studies.

Introducción: El carcinoma adenoneuroendocrino mixto es un tumor raro del tracto gastrointestinal con doble diferenciación en carcinoma adenomatoso y neuroendocrino, cada componente con al menos el 30%. Caso clínico: Mujer de 60 años con cuadro de dolor abdominal agudo. Se decide tratamiento quirúrgico, encontrando un tumor a nivel de ciego y colon ascendente, y se realizan hemicolectomía derecha e ileostomía. Discusión: El carcinoma adenoneuroendocrino mixto puede aparecer en diversos órganos. Son tumores muy malignos, con alto riesgo de metástasis. Conclusiones: Estos tumores no presentan síntomas ni hallazgos radiológicos o de laboratorio específicos; el diagnóstico depende de estudios histopatológicos e inmunohistoquímicos posoperatorios.

Mixed mucinous adenocarcinoma/large cell neuroendocrine carcinoma of the uterine cervix: case report and molecular characterization of a rare entity.

Mixed neuroendocrine-non-neuroendocrine carcinomas of the cervix are rare and generally aggressive diseases. They often present at an advanced stage with hematogenous or lymphatic metastases. The prognosis is poor, mostly influenced by the neuroendocrine component. Unfortunately, the rarity of the disease caused a lack of information about its pathogenesis and molecular landscape. The latest guidelines recommend a multimodal approach that usually includes radical surgery, platinum/etoposide-based chemotherapy, or chemoradiation. Here, we are presenting a case of metastatic mixed adenocarcinoma-large cell neuroendocrine carcinoma of the cervix in a 49-year-old female patient. The molecular characterization of the lesion highlighted the ubiquitous presence of human papillomavirus-18 DNA both in the adenocarcinomatous and the neuroendocrine components, suggesting a role for the virus in the pathogenesis. Moreover, a different set of mutations was detected in the two parts, thus ruling out a possible clonal evolution of the neuroendocrine component from the adenocarcinoma one. More studies are needed to clarify the molecular landscape of these rare lesions and identify putative targets for therapy.

Precise microdissection of gastric mixed adeno-neuroendocrine carcinoma dissects its genomic landscape and evolutionary clonal origins.

Gastric mixed adenoneuroendocrine carcinoma (MANEC) is a clinically aggressive and heterogeneous tumor composed of adenocarcinoma (ACA) and neuroendocrine carcinoma (NEC). The genomic properties and evolutionary clonal origins of MANEC remain unclear. We conduct whole-exome and multiregional sequencing on 101 samples from 33 patients to elucidate their evolutionary paths. We identify four significantly mutated genes, TP53, RB1, APC, and CTNNB1. MANEC resembles chromosomal instability stomach adenocarcinoma in that whole-genome doubling in MANEC is predominant and occurs earlier than most copy-number losses. All tumors are of monoclonal origin, and NEC components show more aggressive genomic properties than their ACA counterparts. The phylogenetic trees show two tumor divergence patterns, including sequential and parallel divergence. Furthermore, ACA-to-NEC rather than NEC-to-ACA transition is confirmed by immunohistochemistry on 6 biomarkers in ACA- and NEC-dominant regions. These results provide insights into the clonal origin and tumor differentiation of MANEC.

Mixed adenoneuroendocrine carcinoma originating from the appendix and colorectum: a comparative analysis of a large population-based database.

PURPOSE: As a rare gastrointestinal neoplasm, the demographic, clinicopathological, and prognostic characteristics of mixed adenoneuroendocrine carcinoma (MANEC) remain unclear. The purpose of this study was to evaluate its biological features, survival outcome, and prognostic factors. METHODS: From the Surveillance, Epidemiology, and End Results (SEER) database, we retrospectively reviewed clinicopathological and survival data of 513 patients who were histopathologically diagnosed with MANEC of the appendix and colorectum bettween 2004 and 2015. The clinicopathological features and survival outcomes of MANEC located at different anatomical locations were compared, and predictive factors for cancer-specific survival (CSS) and overall survival (OS) were assessed. RESULTS: In terms of anatomical distribution of MANEC, the appendix (64.5%, 331/513) was more frequently involved, followed by colon (28.1%, 144/513) and rectum (7.4%, 38/513). The MANEC at different anatomical locations had a distinct clinicopathological characteristic, and colorectal MANEC was significantly associated with more aggressive biological features. The survival outcomes of appendiceal MANEC were significantly better than that of colorectal MANEC (3-year CSS rate 73.8% vs 59.4%, P = 0.010; 3-year OS 69.2% vs 48.3%, P < 0.001). In addition, hemicolectomy had a better survival benefit than appendicectomy for patients with appendiceal MANEC, regardless of lymph node metastasis (P < 0.05). Tumor location, histology grade III, tumor size > 2 cm, T3-T4 stage, lymph node metastasis, and distant metastasis were independent prognostic factors for patients with MANEC. CONCLUSIONS: Tumor location had an important prognostic significance for MANEC. As an uncommon clinical entity, colorectal MANEC had more aggressive biological features and worse prognosis than its appendiceal counterpart. The standard surgical procedure and clinical management strategy for MANEC need to be established.

Mixed Adenoneuroendocrine Carcinoma in the Ampulla of Vater: Case Report

A mixed non-neuroendocrine neuroendocrine neoplasm is a mixed neoplasm with a neuroendocrine component combined with a non-neuroendocrine component. It has a low incidence and limited studies, but with evidence of being an aggressive entity associated with poor survival. We present the case of a 58-year-old woman admitted with clinical symptoms of abdominal pain in the left hypochondrium associated with generalized jaundice and feverish spikes with an imaging diagnosis of bile duct dilation secondary to distal choledocholithiasis. Endoscopic retrograde cholangiopancreatography (ERCP) was performed, finding a significant papilla with a neoplastic appearance, which was biopsied and histopathologically analyzed. The diagnosis of mixed carcinoma with a component of high-grade poorly differentiated neuroendocrine carcinoma and a component of mucinous carcinoma was confirmed. Therefore, we decided to schedule a pancreaticoduodenectomy.

La neoplasia neuroendocrina no neuroendocrina mixta es una neoplasia mixta con un componente neuroendocrino combinado con un componente no neuroendocrino. Esta presenta una incidencia baja y estudios limitados, pero con evidencia de ser una entidad agresiva asociada a una pobre supervivencia. Presentamos el caso de una mujer de 58 años que ingresó por un cuadro clínico de dolor abdominal en el hipocondrio izquierdo asociado a ictericia generalizada y picos febriles con diagnóstico imagenológico de dilatación de la vía biliar secundaria a coledocolitiasis distal, por lo que se realizó una colangiopancreatografía retrógrada endoscópica (CPRE) en la que se encontró una papila mayor de aspecto neoplásico a la cual se le realizó una biopsia analizada histopatológicamente y se confirmó el diagnóstico de carcinoma mixto con componente de carcinoma neuroendocrino pobremente diferenciado de alto grado y componente de carcinoma mucinoso, por lo cual se decidió programar una pancreatoduodenectomía.

Management and outcomes of mixed adenoneuroendocrine carcinoma of the ampulla of Vater: A systematic review and pooled analysis of 56 patients.

BACKGROUND: Tumors of mixed neuroendocrine and nonneuroendocrine histology are classified as collision, combined, or amphicrine and can occur in most organs, including the hepato-pancreato-biliary tract. Given the rarity of mixed adenoneuroendocrine carcinoma (MANEC) of the ampulla of Vater, the patient characteristics, management, and outcomes remain unclear. We sought to systematically review the worldwide literature on ampullary MANECs. METHODS: Eligible studies were identified through a systematic search of the MEDLINE (via PubMed), Scopus, and Cochrane Library databases (end-of-search-date: January 5th, 2022), according to the PRISMA 2020 statement. RESULTS: A total of 39 studies reporting on 56 patients with ampullary MANEC were included. The median age was 63.0 (interquartile range [IQR]: 51.0-69.0) years and 55.6% were male (n = 25/45). Most had combined tumors (64.4%; n = 29/45), followed by collision (24.4%; n = 11/45), and amphicrine tumors (11.1%; n = 5/45). More than half had lymph node metastasis (56.8%; n = 25/44), yet only 7.9% had distant metastasis (n = 3/38). Tumor resection (i.e., mostly pancreaticoduodenectomy) was performed in 96.3% (n = 52/54), followed by adjuvant chemotherapy in 61.8% (n = 21/34). Nearly half experienced disease recurrence (47.2%; n = 17/36) over a median follow-up of 12.0 (IQR: 3.0-16.0) months, and 42.1% (n = 16/38) died over a median follow-up of 12.0 (IQR: 4.0-18.0) months. The most common cause of death was disease progression/recurrence in 81.3% (n = 13/16). CONCLUSION: Early diagnosis and management of ampullary MANEC is challenging yet crucial to improve outcomes since many patients are diagnosed at an advanced disease stage and have unfavorable outcomes. Multicenter granular data are warranted to further understand and improve outcomes in these patients.

Peritoneal metastatic mixed adenoneuroendocrine carcinoma treated with cytoreduction surgery and hyperthermic intraperitoneal chemotherapy: a case report.

A 61-year-old man presented with abdominal distension without any symptoms. On colonoscopy and computed tomography findings, it was clinically diagnosed as peritoneal metastasis of sigmoid colon cancer, and diagnostic laparoscopy was performed. Only the peritoneum was partially resected, and the pathology was signet ring cell carcinoma with predominantly local mucinous carcinoma component. However, the patient complained of persistent symptoms and, despite the progress of chemotherapy, the peritoneal dissemination worsened, and additional cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (HIPEC) was performed. Mixed adenoneuroendocrine carcinomas (MANECs) were reported in the appendix with perforated visceral peritoneum. After additional chemotherapy, the patient was discharged. Patients with advanced MANEC with peritoneal spreading may benefit from aggressive treatment by cytoreduction surgery with HIPEC, followed by intravenous chemotherapy.

Metastasis of Mixed Adenoneuroendocrine Carcinoma of the Uterine Cervix to Thyroid Gland.

The thyroid metastasis from cervical cancer is extremely rare compared to other organs. It is sometimes difficult to distinguish primary tumors from metastases, as most metastatic thyroid nodules are asymptomatic. In this case, a 54-year-old woman had undergone radical hysterectomy due to cervical tumor of stage IB1 mixed adenoneuroendocrine carcinoma (MANEC) 5 years ago. After 3 years, ultrasound examination revealed a suspicious malignant nodule in the left lobe of thyroid gland at regular postoperative follow-up. This patient had no obvious clinical symptoms. The ultrasonography (US)-guided core needle biopsy (CNB) of the thyroid nodule was performed on the patient. The immunohistochemistry analyses revealed that it was poorly differentiated small-cell neuroendocrine carcinoma (SCNEC). Subsequently, the patient underwent left hemithyroidectomy plus isthmusectomy. The postoperative pathology and immunohistochemistry, combining with clinical history, confirmed that the thyroid nodule was a metastasis from cervical MANEC. Conventional chemotherapy and regular follow-up were carried out after the operation. The patient was readmitted 1 year later for pancreatic metastatic lesions and died 1 month after surgery. Early detection of metastatic cancer is potentially helpful, and when necessary, ultrasound-guided puncture biopsy can be utilized to further diagnose metastatic thyroid cancer.

Mixed neuroendocrine-non-neuroendocrine neoplasm arising from long-segment Barrett's esophagus showing exceptionally aggressive clinical behavior.

BACKGROUND: There is only one report of Barrett's esophagus (BE) with mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN). Herein, for the first time, we present a case with an aggressive esophageal MiNEN, as well as with both primary MiNEN and conventional adenocarcinoma, arising in BE. CASE: A 68-year-old woman had been diagnosed with 0-IIa type adenocarcinoma in the background of long-segment BE, 45 months earlier. She underwent endoscopic submucosal dissection (ESD) and the pathological diagnosis was tubular adenocarcinoma, well-differentiated, with slight submucosal invasion. There was no lymphovascular invasion and the margins were intact. The upper esophagogastroduodenoscopy conducted the year after ESD showed no residual or recurrent cancer. However, she was subsequently followed up at another hospital, and endoscopy was not performed after the second year. She was urgently transported to our hospital due to buttock pain in the ninth month of the fourth year. A computed tomography (CT) of the head showed multiple cerebral metastases and positron emission tomography-CT revealed numerous osseous and nodal involvements. We performed upper endoscopy and detected type 3 esophageal tumor. Multiple biopsy specimens histopathologically contained invasive neoplasm composed of neuroendocrine carcinoma (NEC) and adenocarcinoma, moderately to poorly differentiated. The NEC element showed diffuse proliferation of primitive cancer cells possessing fine-granular cytoplasm and nuclei with prominent nucleoli, whereas the adenocarcinoma component had tubules or nested growth of basophilic cells. Immunohistochemically, the NEC cells were diffusely positive for synaptophysin, with focal expressions of INSM1, chromogranin A and NCAM, whereas the adenocarcinoma cells were mostly negative for these NE markers. The Ki67 index was 90% at the hot spots in both types. The patient died 3.5 months after the biopsy-based histological diagnosis. CONCLUSION: Appropriate therapy according to the guidelines and/or meticulous clinical follow-up based on periodic endoscopy as well as a full physical examination are essential, from a proactive perspective, for early diagnosis of secondary aggressive cancers after ESD.

Mixed adenoneuroendocrine carcinoma of the non-ampullary duodenum with mismatch repair deficiency: a rare case report.

A non-ampullary duodenal mixed adenoneuroendocrine carcinoma (MANEC), consisting of a conventional adenocarcinoma and a neuroendocrine carcinoma (NEC), is exceedingly rare. Moreover, mismatch repair (MMR) deficient tumors have recently attracted attention. The patient, a 75-year-old woman with epigastric pain and nausea, was found to have a type 2 tumor of the duodenum, which was diagnosed on biopsy as a poorly differentiated carcinoma. A pancreaticoduodenectomy specimen showed a well-defined 50 × 48 mm tumor in the duodenal bulb, which was morphologically composed of glandular, sheet-like, and pleomorphic components. The glandular component was a tubular adenocarcinoma, showing a MUC5AC-positive gastric type. The sheet-like component consisted of homogenous tumor cells, with chromogranin A and synaptophysin diffusely positive, and a Ki-67 index of 72.8%. The pleomorphic component was diverse and prominent atypical tumor cells proliferated, focally positive for chromogranin A, diffusely positive for synaptophysin, and the Ki-67 index was 67.1%. The sheet-like and pleomorphic components were considered NEC, showing aberrant expression of p53, retinoblastoma, and p16. Notably, all three components were deficient in MLH1 and PMS2. We diagnosed a non-ampullary duodenal MANEC with MMR deficiency. This tumor has a unique morphology and immunohistochemical profile, and is valuable for clarifying the tumorigenesis mechanism of a non-ampullary duodenal MANEC.

Focal neuroendocrine carcinoma mixed with adenocarcinoma of the gallbladder with aggressive lymph node metastasis in a patient who did not meet the mixed neuroendocrine-non-neuroendocrine neoplasm criteria.

A 70-year-old Japanese woman who was treated for interstitial pneumonia (IP) with steroid therapy developed cholecystitis. A serial computed-tomography (CT) imaging showed irregular thickness of the fundus wall of the gallbladder and two rapidly enlarged lymph nodes (LNs): number (no.) 12 and no. 8a. Positron-emission tomography-computed tomography (PET-CT) scan showed an abnormal uptake at the site of the gallbladder tumor and those LNs. We subsequently performed open radical cholecystectomy and LN dissection of the no. 12 and 8a LNs, following complete remission of IP. The histology showed gallbladder adenocarcinoma, with a single focus of neuroendocrine carcinoma (NEC) component of less than 30%; Ki-67 index > 80%, synaptophysin (Syn) (+), chromogranin A (CgA) (+), and clusters of differentiation (CD) 56 (+) (T2bN1M0, Stage IIIB). LN no. 8a was diffusely metastatic with NEC components. LN no. 12c, which was adjacent to the cystic duct, revealed necrosis without apparent tumor cells, but was highly suspicious for tumor necrosis. The final diagnosis was adenocarcinoma of the gallbladder with focal NEC (< 30%), which did not meet the criteria for mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN). Postoperatively, she completed 4 cycles of adjuvant chemotherapy for NEC (Cisplatin plus Etoposide), and no recurrence was observed after 12 months.

Perforated High-Grade Mixed Neuroendocrine Nonneuroendocrine Neoplasm of Cecum: Unusual Presentation of Rare Disease.

Mixed neuroendocrine nonneuroendocrine neoplasms (MiNENs) are rare neoplasms of the gastrointestinal tract, where the neuroendocrine as well as the nonneuroendocrine components each comprise at least 30% of the tumor. Of all cases of colorectal malignancies, MiNENs constitute around 3-9.6%, with only a few cases reported to be arising in the cecum. Since majority present with nonspecific clinical and radiological findings, its diagnosis preoperatively is almost impossible and these are usually diagnosed after histopathological examination of the resected specimen. Owing to the rarity of these tumors as well as lack of complete molecular characterization, optimal treatment remains unestablished. We, here, report a rare case of MiNENs of the cecum infiltrating the right psoas muscle and presenting with perforation for which right hemicolectomy and en bloc excision of the involved psoas muscle was done followed by adjuvant chemotherapy.