MRI findings of rectal submucosal tumors

Unveiling the Rare: A Case Report of Rectal Schwannoma in a Neurofibromatosis Type 1 Patient

Neurofibromatosis type 1 (NF-1) is an autosomal dominant neurocutaneous disorder characterized by skin abnormalities, such as café-au-lait macules and skinfold freckling, as well as peripheral nerve sheath tumors such as neurofibromas, schwannomas, and various other tumors. A 28-year-old man with a history of NF-1 presented to our facility with rectal bleeding. A rectal mass was subsequently discovered on colonoscopy and subsequent imaging. This mass was biopsied with histopathology consistent with a low-grade schwannoma. Schwannomas, while less common in NF-1 than NF-2, do sometimes occur in NF-1 patients, most commonly along the cranial, spinal, or peripheral nerves. These tumors also rarely occur in the gastrointestinal tract and even more rarely within the rectum specifically. Schwannoma must be considered in the differential for any rectal mass discovered in a patient with NF-1, so that the patient can be appropriately managed and treated.

Anal and Perianal Masses: The Common, the Uncommon, and the Rare

A variety of tumors involve the anal canal because the anal canal forms the transition between the digestive system and the skin, and this anatomical region is made of a variety of different cells and tissues. Magnetic resonance imaging (MRI) is the modality of choice for diagnosis and local staging of the anal canal and perianal neoplasms. In this pictorial review, we demonstrate the MRI anatomy of the anal canal and perianal region and display the imaging spectrum of tumors in the region along with an overview of its management. Imaging appearances of many tumorlike lesions that can cause diagnostic dilemmas are also demonstrated with pointers to differentiate between them.

Mucocele: a rare complication following stapled haemorrhoidopexy

Background

Stapled haemorrhoidopexy (SH) has resulted in a unique collection of procedural complications with postoperative mucocele a particularly rare example. This study is designed to comprehensively describe the characteristics of rectal mucocele and discuss its pathogenesis following SH surgery.

Methods

A database of patients presenting with a rectal mucocele following an SH procedure was established and studied retrospectively.

Results

Seven patients (5 males; median age 32 years, range 20–75 years) were identified. All patients complained of variable anal discomfort with 5/7 presenting with inconstant anal pain, 2 with de novo evacuatory difficulty. These cases appeared at a median time of 6 months (range 2–84 months) after SH surgery.

Conclusion

Rectal Mucocele develops when mucosal fragments become embedded and isolated under the mucosa. It is a preventable complication of SH surgery by ensuring correct purse string placement prior to stapled haemorrhoid excision.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12893-022-01744-3.

Magnetic Resonance Imaging in Giant Perianal Epidermoid

Perianal epidermoid cyst is a rare entity and is commonly diagnosed late owing to its slow-growing nature. Imaging plays a vital role in diagnosis and differentiation from other cysts such as dermoid, tailgut, and rectal duplication cysts. Magnetic resonance imaging (MRI) is the preferred modality as uncomplicated cases show typical signal changes. Diffusion-weighted imaging has a definite additional role. We report a case of a giant perianal epidermoid diagnosed on MRI and successfully managed surgically.

Cellular Angiofibroma Presenting as a Subepithelial Rectal Mass

A very rare case of cellular angiofibroma arising from the rectum in a 62-year-old man with a normal colonoscopy 2 years earlier is reported. To our knowledge, this is the first such case reported in the literature. The tumor was transanally excised with clear margins, and the patient had no postoperative complications. It is key to accurately differentiate this lesion from other subepithelial rectal tumors and more aggressive genital soft tissue tumors because clinical management varies. We performed a review of clinical records and pathology as well as an extensive literature review.

Beyond adenocarcinoma: MRI of uncommon rectal neoplasms and mimickers

OBJECTIVE

To provide a review of rare rectal tumors beyond adenocarcinoma.

RESULTS

Rectal cancer is a common malignancy, both in the United States and abroad. In addition to adenocarcinoma, abdominal radiologists will encounter a variety of other less common rectal masses, both benign and malignant neoplasms as well as non-neoplastic mimickers. Familiarity with these conditions and their characteristic features on MRI is useful in clinical practice. In this article, a number of such conditions are discussed, with an emphasis on distinguishing features on MRI of the rectum.

CONCLUSION

Familiarity with the MRI features of rare rectal tumors beyond adenocarcinoma, as well as a small number of non-neoplastic mimics, is important for abdominal imagers to make diagnostic differentials and to assist in treatment planning.

Multimodality Imaging Review of Anorectal and Perirectal Diseases With Histological, Endoscopic, and Operative Correlation, Part I: Anatomy and Neoplasms

A broad spectrum of pathology affects the rectum, anus, and perineum and understanding of its relevant anatomy is important in accurate reporting, particularly in rectal cancer. In this pictorial essay, correlative imaging, endoscopic, pathologic, and operative images are presented to illustrate normal anorectal anatomy and neoplastic conditions that affect the anus and rectum. A particular case-based focus is given to rectal adenocarcinoma with pelvic MR and surgical histopathology. Additionally, carcinoid tumor, gastrointestinal stromal tumor, condylomata acuminata, squamous cell carcinoma, melanoma, and metastatic disease about the rectum and anus are reviewed.

The bottom line: MRI and CT findings of unusual rectal and perirectal pathology

Although common nonspecific symptoms (i.e., rectal bleeding, pelvic pressure, and change in bowel habits) are associated with rectal cancer, occasionally these are related to a different underlying disease. Over the past few years, considerable progress has been made in imaging of the rectum. Specifically, new magnetic resonance techniques and capabilities provide impressive high-resolution assessment of the rectal wall and enable evaluation and characterization of the perirectal tissues. This paper reviews imaging findings of uncommon causes of rectal and perirectal pathology that may be clinically confounded with rectal cancer. Radiologists need to be aware of uncommon pathologies in this region in order to facilitate optimal management decisions.

Extranodal lymphomas of abdomen and pelvis: imaging findings and differential diagnosis

A wide spectrum of extranodal lymphomas in the abdomen and pelvis is commonly encountered by imaging. Diagnosing these lesions generally requires a multimodality approach. This review highlights imaging appearances of extranodal lymphomas in the abdomen and pelvis with emphasis on computed tomography, magnetic resonance imaging, and positron emission tomography-computed tomography along with the relevant differential diagnosis.

Pathology Report: Presacral Noncommunicating Enteric Duplication Cyst

BACKGROUND

Gastrointestinal (GI) tract duplication cysts or enteric duplication cysts are rare congenital malformations sometimes found on the mesenteric aspect of segments of the alimentary tract. Enteric duplication cysts are lined by normal GI epithelium and may be classified as foregut, mid-gut, and hindgut cysts. Except in very rare cases of retroperitoneal enteric duplication cysts, these cysts communicate with the GI tract and share a common blood supply. Concurrent congenital malformations are not uncommon and malignant transformation within enteric duplication cysts has also been reported.

METHODS

We describe a case of a noncommunicating enteric duplication cyst in a 52-year-old woman.

RESULTS

The patient presented with a presacral cystic mass requiring frequent drainage procedures that was primarily believed to be of neural origin. Upon resection, the lesion contained heterotopic tissue, including ciliated bronchial epithelium, squamous and transitional epithelia, and pancreatic and gastric tissue. Focal, low-grade intestinal adenoma was present, but malignancy was not detected in this case.

CONCLUSION

To our knowledge, this is the sixth reported case of a noncommunicating enteric duplication cyst in the English medical literature.

Review article: the investigation and management of rectal neuroendocrine tumours

BACKGROUND

Rectal neuroendocrine tumours (NETs) are increasingly identified at endoscopy possibly as a result of bowel cancer screening programmes.

AIM

To present a review of the literature to aid clinicians in the diagnosis and management of rectal neuroendocrine tumours.

METHODS

A literature search was conducted through MEDLINE using search terms: rectal, rectum, carcinoid, NET, therapy, endoscopy, mucosal resection, submucosal dissection. Relevant articles were identified through manual review with reference lists reviewed for additional articles.

RESULTS

The incidence of rectal neuroendocrine tumours is approximately 1 per 100 000 population per year with the majority (80-90%) being <1 cm and localised to the submucosa. Metastatic disease is infrequent (<20%) with risk factors including size, atypical appearance, grade and depth of invasion. The primary resection modality influences complete resection rates and the need for secondary therapy. A thorough pre-resection diagnostic work up is required for lesions that are at higher risk of invasion and metastasis. Device-assisted endoscopic mucosal resection and endoscopic submucosal dissection are used to resect localised rectal neuroendocrine tumours <2 cm. Transanal surgery is also used to resect localised 1-2 cm rectal neuroendocrine tumours. Oncological surgical resection is used for rectal neuroendocrine tumours that are >2 cm or with invasion and regional disease. The treatment of advanced disease is multimodal.

CONCLUSIONS

The long-term tumour biology of small rectal neuroendocrine tumours remains unclear. There is uncertain impact from bowel cancer screening programmes on rectal neuroendocrine tumour incidence, morbidity and mortality. Referral to neuroendocrine tumour centres for patients with locally advanced disease or metastatic disease is recommended.

Benign and malignant tumors of the rectum and perirectal region

Although most rectal masses are histologically characterized as adenocarcinomas, the rectum and perirectal region can be affected by a wide variety of tumors and tumor-like conditions that can mimic the symptoms caused by rectal adenocarcinoma, including mucosal or submucosal rectal tumors such as lymphoma, gastrointestinal stromal tumor, leiomyosarcoma, neuroendocrine tumor, hemangioma, and melanoma, as well as tumors of the perirectal region such as developmental cyst, neurogenic tumor, osseous tumor, and other miscellaneous conditions. As a group, tumors of the rectum are considerably different from the group of tumors that arise in the perirectal region: they are most often neoplastic, symptomatic, and malignant, whereas tumors arising in the perirectal region are most commonly congenital, asymptomatic, and benign. Proctoscopy with biopsy is the most important method for the diagnosis of rectal tumors, but this procedure cannot determine the precise intramural extension of a rectal tumor and cannot accurately distinguish submucosal and intramural tumors from extramural tumors. Cross-sectional imaging, especially transrectal ultrasound and magnetic resonance imaging, allows evaluation of the entire bowel wall thickness and the perirectal tissues, helping further characterize these tumors. Recognition of the existence of these masses and their key clinical and imaging features is crucial for clinicians to accurately diagnose and appropriately manage these conditions.

MRI features of gastrointestinal stromal tumors

OBJECTIVE

The purpose of this study was to investigate the MRI features of gastrointestinal stromal tumors (GISTs) with special emphasis on the dynamic enhancement pattern and findings of diffusion restriction.

MATERIALS AND METHODS

Forty-two patients with pathologically proven GISTs who underwent MRI that included dynamic contrast-enhanced and diffusion-weighted imaging (DWI) were included in this study. Two abdominal radiologists analyzed the MR images in consensus regarding the morphologic features, enhancement degree and pattern, and findings of diffusion restriction. The mean apparent diffusion coefficient (ADC) values of the tumors were measured by one of the radiologists. The MRI features and mean ADC values were analyzed with respect to tumor size and malignancy risk.

RESULTS

Small GISTs (≤ 5 cm, n = 25) appeared as round tumors with strong and homogeneous arterial enhancement and a persistent enhancement pattern. Large GISTs (> 5 cm, n = 17) appeared as lobulated tumors with mild heterogeneous gradual enhancement, and they frequently exhibited intratumoral cystic change (n = 13). The prevalence of intratumoral cystic change was higher in the moderate to high risk group than in very low to low risk group (p < 0.05). There was negative linear correlation between the mean ADC values and the malignancy risk of GISTs (r = -0.670, p < 0.05).

CONCLUSION

Small GISTs had MRI features different from the well-known imaging features of large GISTs. The presence of intratumoral cystic change and a low mean ADC value may be helpful for predicting the high malignancy potential of GISTs.

What is hiding in the hindgut sac? Looking beyond rectal carcinoma

Objectives

Although rectal cancer is by far and large the most common pathology involving the rectum that needs imaging, there are many other important but less common pathological conditions affecting anorectal region. The objective of this pictorial review is to discuss the cross-sectional imaging features of less common anorectal and perirectal diseases.

Results

Although a specific histological diagnosis cannot usually be made due to considerable overlap in the imaging appearances of anorectal diseases, this review illustrates the cross-sectional imaging findings with emphasis on magnetic resonance imaging (MRI) that can help in narrowing down the differentials to a reasonable extent.

Teaching points

• Variety of pathology exists in the anorectum apart from common rectal carcinoma

• Anorectal diseases present as non-specific wall thickening indistinguishable from rectal carcinoma

• Computed tomography (CT) and MRI can help in narrowing down the differentials, although often biopsy is warranted.

Rectum sarcoma: challenging diagnostic and therapeutic modalities

INTRODUCTION

Sarcomas are malignant tumors that arise from mesenchymal tissue at any of the body sites. They incorporate the wide category of GISTs and are classified in various histological types. Histological grading is another indicator of the degree of malignancy, the probability of distant metastases, and survival but remains a poor definition of local recurrence.

DISCUSSION

The size and depth of invasion are the most important prognostic factors. Since they grow within the intestinal wall, the symptoms are usually few or late, leading to delays in diagnosis. Most common signs are rectal bleeding, abdominal or anal pain, diarrhea, tenesmus and weight loss. The diagnostic and staging protocol of stromal tumors of the rectum includes mainly endoscopic surveillance, computed tomography, and magnetic resonance imaging. Therefore, rectum sarcoma (RS) consists one of the most biologically virulent cancers and is difficult to cure by conventional procedures. The treatment is primarily surgical, where possible, and should guarantee complete clearance of the tumor, which often requires an aggressive approach. Unfortunately, the minority of patients is eligible to undergo surgical intervention. In addition, surgical removal of RS does not necessarily indicate a patient's long-term recovery. Alternative therapies, such as radio- and chemotherapy, proved insufficient. Elucidation of its molecular basis may prove useful in developing and identifying prognostic biomarkers.