An unusual case of colonic mixed adenoendocrine carcinoma: collision versus composite tumor. A case report and review of the literature

Appendiceal collision tumors: case reports, management and literature review

Appendiceal tumors are incidentally detected in 0.5% cases of appendectomy for acute appendicitis and occur in approximately 1% of all appendectomies. Here, we report two cases of appendiceal collision tumors in two asymptomatic women. In both cases, imaging revealed right-lower-quadrant abdominal masses, which were laparoscopically resected. In both cases, histological examinations revealed an appendiceal collision tumor comprising a low-grade appendiceal mucinous neoplasm and well-differentiated neuroendocrine neoplasm (NEN). For complete oncological control, right hemicolectomy was performed in one patient for the aggressive behavior of NEN; however, histology revealed no metastasis. The other patient only underwent appendectomy. No further treatment was recommended. According to the latest guidelines, exact pathology needs to be defined. Proper management indicated by a multidisciplinary team is fundamental.

Composite intestinal adenoma-microcarcinoid: An update and literature review

Composite intestinal adenoma-microcarcinoid (CIAM) is a rare intestinal lesion consisting of conventional adenoma and small, well differentiated carcinoid [microcarcinoid (MC)] at its base. The incidence of CIAM is 3.8% in surgically resected colorectal polyps. While its pathogenesis is unknown, studies support the role of Wnt/β-catenin pathway in the tumorigenesis of CIAM. CIAMs have been primarily reported in the colon wherein they present as polyps with well-defined margins, similar to conventional adenomatous polyps. MC is usually found in adenomatous polyps with high-risk features such as large size, villous architecture, or high grade dysplasia. Histologically, the MC component is often multifocal and spans 3.9 to 5.8 millimeters in size. MC is usually confined within the mucosa but occasional CIAM cases with MC extending to the submucosa have been reported. MC of CIAM demonstrates bland cytology and inconspicuous proliferative activity. The lesional cells are positive for synaptophysin and 60% to 100% of cases show nuclear β-catenin positivity. MC poses a diagnostic challenge with its morphologic and immunohistochemical resemblance to both benign and malignant lesions, including squamous morules/metaplasia, adenocarcinoma, squamous cell carcinoma, sporadic neuroendocrine tumor and goblet cell adenocarcinoma. CIAM is an indolent lesion with a favorable outcome. Complete removal by polypectomy is considered curative. Awareness and recognition of this rare entity will help arrive at correct diagnosis and improve patient care. Currently, CIAM is not recognized as a subtype of mixed neuroendocrine-non-neuroendocrine neoplasm by WHO.

A Low-Grade Appendiceal Mucinous Neoplasia and Neuroendocrine Appendiceal Collision Tumor: A Case Report and Review of the Literature

Patient: Female, 31-year-old

Final Diagnosis: Appendiceal neuroendocrine tumor • low-grade appendiceal mucinous neoplasm

Symptoms: Abdominal pain • dysuria

Medication: —

Clinical Procedure: Laparoscopic appendicectomy • laparoscopic right hemicolectomy

Specialty: Oncology • Surgery

Mixed epithelial endocrine neoplasms of the colon and rectum – An evolution over time: A systematic review

BACKGROUND

Mixed tumors of the colon and rectum, composed of a combination of epithelial and endocrine elements of benign and malignant potential are rare neoplasms. These can occur anywhere in the gastrointestinal tract and are often diagnosed incidentally. Though they have been a well-documented entity in the pancreas, where the exocrine-endocrine mixed tumors have been known for a while, recognition and accurate diagnosis of these tumors in the colon and rectum, to date, remains a challenge. This is further compounded by the different terminologies that have been attributed to these lesions over the years adding to increased confusion and misclassification. Therefore, dedicated literature reviews of these lesions in the colon and rectum are inconsistent and are predominantly limited to case reports and case series of limited case numbers. Though, most of these tumors are high grade and of advanced stage, intermediate and low grade lesions of these mixed tumors are also increasingly been reported. There are no established independent consensus based guidelines for the therapeutic patient management of these unique lesions.

AIM

To provide a comprehensive targeted literature review of these complex mixed tumors in the colon and rectum that chronicles the evolution over time with summarization of historical perspectives of terminology and to further our understanding regarding their pathogenesis including genomic landscape, clinicoradiological features, pathology, treatment, prognosis, the current status of the management of the primary lesions, their recurrences and metastases.

METHODS

A comprehensive review of the published English literature was conducted using the search engines PubMed, MEDLINE and GOOGLE scholar. The following search terms [“mixed tumors colon” OR mixed endocrine/neuroendocrine tumor/neoplasm/lesion colon OR adenocarcinoma and endocrine/neuroendocrine tumor colon OR mixed adenocarcinoma and endocrine/neuroendocrine carcinoma colon OR Amphicrine tumors OR Collision tumors] were used. Eligibility criteria were defined and all potential relevant items, including full articles and/or abstracts were independently reviewed, assessed and agreed upon items were selected for in-depth analysis.

RESULTS

In total 237 full articles/abstracts documents were considered for eligibility of which 45 articles were illegible resulting in a total of 192 articles that were assessed for eligibility of which 139 have been selected for reference in this current review. This seminal manuscript is a one stop article that provides a detailed outlook on the evolution over time with summarization of historical perspectives, nomenclature, clinicoradiological features, pathology, treatment, prognosis and the current status of the management of both the primary lesions, their recurrences and metastases. Gaps in knowledge have also been identified and discussed. An important outcome of this manuscript is the justified proposal for a new, simple, clinically relevant, non-ambiguous terminology for these lesions to be referred to as mixed epithelial endocrine neoplasms (MEENs).

CONCLUSION

MEEN of the colon and rectum are poorly understood rare entities that encompass an extensive range of heterogeneous tumors with a wide variety of combinations leading to tumors of high, intermediate or low grade malignant potential. This proposed new revised terminology of MEEN will solve the biggest hurdle of confusion and misclassification that plagues these rare unique colorectal neoplasms thus facilitating the future design of multi institutional prospective randomized controlled clinical trials to develop and evaluate newer therapeutic strategies that are recommended for continued improved understanding and personal optimization of clinical management of these unique colorectal neoplasms.

Management and outcome of an appendiceal collision tumour composed of neuroendocrine and mucinous neoplasms

We report an appendiceal collision tumour in a 23-year-old woman who presented with constipation and abdominal fullness. Imaging revealed a right lower quadrant abdominal mass that was laparoscopically resected. Histology revealed an appendiceal collision tumour composed of a low-grade mucinous neoplasm and well-differentiated neuroendocrine neoplasm. A right hemicolectomy for complete oncological control was performed revealing metastatic spread of the neuroendocrine component to the lymph nodes. No further treatment was recommended and the patient was followed with expectant management. At 2-year follow-up, no evidence of disease was found on surveillance imaging. Appendiceal collision tumours can arise in young adults; treatment should be guided by oncological principles of the component tumours.

Mixed adenoneuroendocrine carcinoma of the colon and rectum

Mixed adenoneuroendocrine carcinoma (MANEC) are rare cancers of the gastrointestinal (GI) and pancreatobiliary tract. They are characterized by the presence of a combination of epithelial and neuroendocrine elements, where each component represents at least 30% of the tumour. Review of literature and consolidation of clinicopathological data. Sixty-one cases of colorectal MANEC have been reported in literature and one seen in this centre. The median age of the patients affected was 61.9 ± 12.4 years (20-94 years). Male to female ratio is 1.0:1.2. Presentations were similar to other colorectal malignancies. 58.0% of colorectal MANECs were found in the right colon, 8.1% cases in the transverse, 16.1% in the left colon, 16.1% in the rectum. These tumours appeared invasiveness 79.1% were T3-T4. Over 90% of cases were presented with metastatic disease. The majority of patient underwent surgical resection of the primary cancer (96.6%). Of these, 10 operations (17.9%) were emergency operations due to obstruction, perforation, or bleeding. Three patients received first line palliative care. In eight cases (13.8%), patients underwent adjuvant chemotherapy. The median overall survival after diagnosis was 10 ± 2.4 months (95% CI: 5.37-14.64 months). MANECs are rare but aggressive colorectal cancers. Surgical resection of localized disease with adjuvant chemotherapy appears to significantly improve survival in small case series. Further understanding through the sharing of experiences is required.

Rare Collision Tumor of the Biliary Tract

Malignancies of the gallbladder are uncommon in the developed world. Collision tumors are also extremely rare neoplastic phenomena. Given their scarcity, there are no guidelines for treatment, and prognosis is based on the more aggressive tumor type. We present a patient with a collision tumor consisting of signet-ring cholangiocarcinoma and large-cell neuroendocrine gallbladder carcinoma of the biliary tract, and we review the literature pertaining to biliary tract collision tumors and their management.

Coexisting tubular adenoma with a neuroendocrine carcinoma of colon allowing early surgical intervention and implicating a shared stem cell origin

High-grade colonic neuroendocrine carcinomas (NECs) are uncommon but extremely aggressive. Their co-existence with tubular adenoma (TA) has rarely been reported. We present a 68-year-old man who was found on routine colonoscopy to have multiple colorectal TAs and an ulcerated lesion in the ascending colon. Microscopically, a poorly-differentiated invasive carcinoma juxtaposed with a TA was identified. Differential diagnosis included a poorly-differentiated adenocarcinoma, medullary carcinoma, high-grade NEC and lymphoma. The immunohistochemical profile showed positive staining for keratins, synaptophysin and chromogranin but negative for LCA, CDX2, CK7, CK20, TTF-1 and PSA, supporting the NEC diagnosis. Upon subsequent laparoscopic right hemicolectomy, the tumor was identified as a 3.0 cm umbilicated and ulcerated mass with an adjacent TA. Both TA and NEC showed positive staining for β-catenin indicating a shared colonic origin. The mitotic counts (77/10 high power fields) and a high proliferation rate (75% by Ki-67) corroborated a high-grade stratification. Mutational analysis indicated a wild-type BRAF and KRAS with mismatch repair proficiency. The AJCC (7^th edition) pathologic stage is pT3, pN0, pMx. The patient received adjuvant chemotherapy with cisplatin/etoposides for three cycles and will be followed up for a year to detect recurrence. In conclusion, the co-existence of TA with high grade-NEC in our case allowed early identification and intervention of the otherwise asymptomatic but aggressive tumor. In addition, the finding of a high-grade NEC within a large TA in this case suggests a link between the two lesions and could represent a shared stem cell origin.

Presence of Cytokeratin 19-Expressing Cholangiocarcinoma-Like Tumour in a Liver Metastatic Lesion of Rectal Neuroendocrine Tumour

Introduction

Tumours with adenocarcinoma and neuroendocrine components have often been reported, although the reason underlying the dual components remains unclear.

Case Presentation

A 43-year-old woman with multiple liver metastatic lesions of rectal neuroendocrine tumour underwent primary tumour resection and subsequent liver transplantation. Pathological examination indicated a cholangiocarcinoma-like tumour with gland formation, adjacent to a liver metastatic lesion of the neuroendocrine tumour. This tumour comprised atypical columnar epithelium, and stained positively for neuroendocrine markers and the ductal marker cytokeratin 19, indicating amphicrine properties and a partial cholangiocarcinoma phenotype – features not observed in the primary and metastatic neuroendocrine tumours.

Conclusion

The presence of adenocarcinoma only at the metastatic site indicated that neuroendocrine tumour cells acquired stemness and differentiated into adenocarcinoma through metastasis, or that the adenocarcinoma newly arose from the adjacent epithelium influenced by the neuroendocrine tumour. We propose a novel mechanism for the pathogenesis of mixed tumours in neuroendocrine tumours.

Large cell neuroendocrine - Adenocarcinona mixed tumour of colon: Collision tumour with peculiar behaviour. What do we know about these tumours?

Introduction

Mixed glandular-endocrine carcinomas are rare tumours of gastrointestinal tract (MANEC). They are more frequent in stomach and hardly one hundred cases have been described in colon. According to Lewis, they are classified into collision (side by side pattern), composite (intermingled) or amphicrine (neuroendocrine and glandular features inside a same cell). Collision tumours are related to biclonal theory: two simultaneous cancerogenic events. Conversely, multidirectional differentiation from a stem cell is accepted as origin of composite tumours.

The aim of this paper is to analyse the behaviour of these tumours, with an especial concern about how these tumours metastasise, and the different theories about carcinogenesis.

Presentation of case

We report a rare case of collision adenocarcinoma-large cell neuroendocrine tumour of colon that after a three-year period of follow-up has presented a retroperitoneal recurrence that features adenocarcinoma and large cell neuroendocrine components.

Discussion

After an exhaustive review of the English literature, we found that only two cases of collision tumour of colon with metastases showing glandular and endocrine components have been described up to date, so we report the third case, and the first happening in transverse colon.

Conclusion

We conclude that not all collision tumours follow the biclonal theory and more studies are needed to clarify the origin of these neoplasms, and consequently, to reach an adequate treatment.

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MANEC are defined as mixed adenoneuroendocrine carcinoma.

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They are divided into composite and collision.

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The poorest differentiated component will determine the prognosis.

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Metastases occur frequently at liver and nodes.

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Colon is a very rare place.

[A case of colonic collision tumor (adenocarcinoma and neuroendocrine carcinoma)]

Collision tumors of the colon are rare. A 54-year-old man was referred to our hospital for the evaluation of hematochezia. Colonoscopy demonstrated the presence of about 3 cm sized mass in the rectosigmoid junction. After surgical resection, the colonic lesion was histologically composed of two discrete lesions: adenocarcinoma in the superficial layer and poorly differentiated neuroendocrine carcinoma in the deeper layer. We report this case of colonic collision tumor (adenocarcinoma and neuroendocrine carcinoma) with a review of the literature.

Colonisation of basal cell carcinoma and actinic keratosis by malignant melanoma in situ in a patient with xeroderma pigmentosum variant

Although malignant melanoma (MM) and both basal cell carcinoma (BCC) and actinic keratosis (AK) are sun-induced lesions, the coexistence of these entities at the same anatomical site (collision tumour) is exceedingly rare. We report the case of a 54-year-old woman with a known history of xeroderma pigmentosum variant (XPV) who presented with 2 separate skin lesions over the middle and upper right forearm, respectively. The clinical impression was that of BCCs or squamous cell lesions. On histological examination, both specimens showed features of melanoma in situ (MIS). In the first lesion, MIS merged with and colonised a superficial and focally invasive BCC. In the second lesion, MIS merged with an AK. No separate invasive nests of malignant melanoma were seen in either specimen. The atypical melanocytes were highlighted by Melan-A and HMB-45 immunostaining, whereas the epithelial cells in both the BCC and AK stained with the pancytokeratin MNF-116. The patient had a previous history of multiple MMs and non-melanomatous skin cancers and finally developed widespread metastatic malignant melanoma, which proved fatal. The rare and interesting phenomenon of collision tumours may pose diagnostic difficulties. To our knowledge, this is the first reported simultaneous presentation of cytologically malignant collision tumours in a patient with XPV.

Mixed adenocarcinoma-carcinoid (collision tumor) of the appendix

OBJECTIVE

To report a case of mixed adenocarcinoma and carcinoid in the gastrointestinal tract.

CLINICAL PRESENTATION AND INTERVENTION

A 52-year-old man presented with a mass at the base of the appendix. On microscopic examination of the tumor, mixed adenocarcinoma and carcinoid was identified. The carcinoid component was insular/trabecular in morphology, and the epithelial component revealed mucinous adenocarcinoma. Morphologically and immunohistochemically the 2 components showed a clear-cut distinction, without any intervening intermediate cell population. The adenocarcinomatous component displayed omental deposit and metastasis to the regional lymph nodes. One year later, the patient developed multiple metastatic deposits of adenocarcinoma in the liver, rectus muscle, ileum and sigmoid colon.

CONCLUSION

This tumor had an aggressive clinical course and behaved more like adenocarcinoma than carcinoid.

Synchronous collision malignant melanoma and adenocarcinoma of the rectum

"Collision tumors" consist of two independent but coexisting tumors. This uncommon situation might be easily mistaken for a composite tumor where one histogenetic event originates from two apparently distinct neoplasms. Colorectal collisions are particularly unusual; here, we report the exceedingly rare case of a 61-year-old man with malignant melanoma and adenocarcinoma colliding in the rectum. Collision tumors have an idiopathic pathophysiology and in fact "accidental meeting" is accepted by many authors. This article discusses the concepts about cancer development, which are overlooked by this hypothesis, another theory to explain that this rare occurrence involves microenvironment changes.