Clinical Case Summary

A 65-year-old female with recurrent episodes of rectal bleeding consulted the emergency department. A digital rectal examination showed bright red blood on admission, and a complicated mass was palpated. Routine blood tests and other clinical studies were unremarkable. Colonoscopy revealed a 7 cm blackish, friable rectal tumor protruding from the anal canal (Figure 1).
According to the histopathology report, intraepithelial melanocytes abnormally proliferated, with positive Melan-A and HMB45, indicating malignant anorectal melanoma. Chest, abdominal, and pelvic CT scans were negative for metastatic disease. However, a pelvic MRI revealed an anal canal tumor directly invading the internal sphincter and extending to the lower rectum, involving two regional lymph nodes and no obstruction signs.
A positron emission tomography scan confirmed an intensely hypermetabolic lesion centered on the anorectal region (standardized uptake value = 28), with no distant metastases. According to the diagnostic workup findings, the multidisciplinary oncology board proceeded with abdominoperineal resection (APR) without neoadjuvant immunotherapy (Figure 2).
Anorectal melanoma accounts for 1%–1.9% of rectal cancers and<2% of all melanomas (1). In the United States, it occurs in 0.27 cases per 1 million population annually in an upward trend (1). Primary lesion sites include below the dentate line (42.7%), around the dentate line (33.3), and above the dentate line (23.9%) (2). Typical clinical manifestations are fresh rectal bleeding, anal mass sensation, and tenesmus (3). Surgery, which includes APR or wide local excision, remains the cornerstone of treatment for early-stage anorectal melanoma (3).

References

1. Coté TR, Sobin LH. Primary melanomas of the esophagus and anorectum: epidemiologic comparison with melanoma of the skin. Melanoma Res 2009;19:58-60.
2. Bello DM, Smyth E, Perez D, et al. Anal versus rectal melanoma: does site of origin predict outcome? Dis Colon Rectum 2013;56:150-7.
3. Meguerditchian AN, Meterissian SH, Dunn KB. Anorectal melanoma: diagnosis and treatment. Dis Colon Rectum 2011;54:638-44.

Clinical Case Summary

Isolated cecal necrosis is a rare variant of ischemic colitis, more commonly seen in elderly patients with comorbidities. It is an uncommon cause of an acute abdomen and is a differential diagnosis to consider in patients with right lower quadrant abdominal pain.
Case report: A 51-year-old man, with a history of type 1 diabetes mellitus and end-stage chronic kidney disease, on a regular hemodialysis program, attended the emergency department for abdominal pain in the lower right quadrant and bloodless diarrhea, with a 12-hour evolution. On physical examination, he had a painful abdomen on palpation of the right quadrants. The analyses showed leukocytosis 12200/ul and C-reactive protein 190 mg/L. Abdominal computed tomography (CT) scan showed diffuse parietal thickening of the ascending colon measuring approximately 10 cm in length, associated with densification of the surrounding mesenteric fat and small locoregional ganglia, favoring the hypothesis of inflammatory pathology. Given the diagnostic doubt raised by the imaging examination and its impact on the therapy to be instituted, it was decided to perform a colonoscopy, which revealed the cecum mucosa and ileocecal valve with a black color, with superficial ulceration of the proximal limit with an abrupt transition to normal colic mucosa. Biopsies of the cecum were taken and histology confirmed the diagnosis of severe ischemic colitis (necrosis). Considering that CT did not reveal complications and the patient's surgical risk, conservative therapy was decided, with fluid therapy and antibiotic, and the patient had a favorable evolution.

References

Çakar E, Ersöz F, Bag M, Bayrak S, Çolak Ş, Bektaş H, Güneş ME, Çakar E. Isolated cecal necrosis: our surgical experience and a review of the literature. Ulus Cerrahi Derg. 2014 Dec 1;30(4):214-8.

Disclosure

Nothing to disclosure

Clinical Case Summary

A 48-year-old man with a history of symptomatic hemorrhoids diagnosed a years earlier, complained of new intermitent rectal bleeding in the last month. We decided to do a colonoscopy were we found a pedicled polyp with a head of about 15mm with blackish areas on the anopectineal line and with blackish dots in the arising region (image 1-2). Biopsies gave us the diagnosis of melanoma (immunohistochemistry s-100 and Melan-A positive, cytokeratin AE1/AE3 and CD 117 negative). PET-CT was performed with intense uptake of the radiotracer in the same place, without pathological adenopathies (image 3). This case was discussed in a multidisciplinary session, and taking into account the age of the patient and the doubts of the depth and the existence of satellitosis, we decided to make a surgical treatment (abdominoperineal amputation) with a laparoscopic gamma camera. The pathological anatomy was conclusive with melanoma of the rectal mucosa (tumor thickness 1.5cm) without satellite nodules or affected lymph nodes.
Anorectal melanoma (AM) is a rare neoplasm, accounting for <1% of anorectal malignancies and around 1-2% of all melanomas. The treatment is based on surgery (local or radical), it is resistant to chemotherapy and the role of radiotherapy is highly controversial.
It is a highly lethal disease that reappears in 80% of cases after surgery, with a 5-year survival of 12-15% (30 months if the tumor does not exceed the muscularis propria or 22 months if it exceeds it, even though there is no locoregional lymphadenopathy or distant metastases).
AM, can be pigmented or not, flat, polypoid or ulcerated being easily mistaken with a thrombosed hemorrhoid. The symptoms may also be similar; such as rectal bleeding, pain, pruritus, tenesmus, or change in bowel habits. To mistake AM with hemorrhoids showed a negative impact in survival patients with AM, which reflects the importance of not trivializing the anorectal symptoms and perform a good clinical and endoscopic inspection.

References

-José Donizeti de Meira Júnior, B , C , E , F Lucas Faraco Sobrado, D , E Vivian M. Guzela, et al. Anorectal Mucosal Melanoma: A Case Report and Literature Review. Am J Case Rep. 2021; 22: e933032-1–e933032-5.
-Huang WF, Wang X, Liu W.Primary Malignant Anorectal Melanoma. J Gastrointest Surg. 2022 Jan;26(1):263-265
-Reina A, Errasti J, Espin E. Melanoma anorrectal. Revisión de conjunto. Cir esp. 2014; 92(8):5 1 0 – 5 1 6
-Nigam JS, Nishit, Kumar T, Singh A, et al Tewari P.Anorectal Melanoma-Brownish Black Mass Not Always a Hemorrhoid. J Gastrointest Cancer. 2022 Sep;53(3):825-829

Disclosure

I have no conflicts of interest

Clinical Case Summary

Introduction: Heterotopic gastric mucosa (HGM) is not uncommon throughout the gastrointestinal (GI) tract, nevertheless its presence in the lower GI is considered as a rare entity. The purpose of this study is to report a clinical case of HGM located in the rectum, which was presented with intermittent bleeding. The medical history of the patient and the way was treated are presented.
Case presentation: A 40-year-old male patient with an unremarkable medical history presented to the outpatient clinic suffering from anal pain, accompanied with intermittent rectal bleeding. At colonoscopy, a solitary flat elevated lesion with central depression, approximately 2 cm in size, was identified in the lower part of the rectum. Histological examination of the biopsy specimen showed heterotopic gastric mucosa while Giemsa stain was positive for Helicobacter Pylori (HP). First-line treatment for HP eradication including a 14-day course of proton pump inhibitor (PPI), amoxicillin, clarithromycin and metronidazole was administered. One month after therapy was completed, the patient underwent a Urea Breath Test (UBT) and an HP antigen stool examination, which were both negative. Meanwhile, the symptoms had been resolved. Unfortunately, the patient never returned to follow the standard procedure of proper clinical and endoscopic re-evaluation.
Conclusion: HGM can be either congenital, as a result of an error in the differentiation of the endodermal stem cells during organogenesis, or acquired, as a metaplasia during the repair of damaged epithelium. When located in rectum, HGM can be presented with symptoms such as bleeding, abdominal or anal pain. Moreover, complications such as ulcer and even adenocarcinoma have been reported. Although endoscopic or surgical resection is considered as the radical therapy of the HGM in rectum, administration of PPIs, inhibitors of histamine-receptors or HP eradication treatment, in cases HP is present, is effective in short-term symptoms relief.

References

1) Iacopini F, Gotoda T, Elisei W, Rigato P, Montagnese F, Saito Y, Costamagna G, Iacopini G. Heterotopic gastric mucosa in the anus and rectum: first case report of endoscopic submucosal dissection and systematic review. Gastroenterol Rep (Oxf). 2016 Aug;4(3):196-205. doi: 10.1093/gastro/gow006. Epub 2016 Apr 21. PMID: 27103738; PMCID: PMC4976682.
2) Devereaux CE, Devereaux RG. Heterotopic gastric mucosa of the rectum with a review of the literature. J Clin Gastroenterol. 1994 Jul;19(1):41-5. doi: 10.1097/00004836-199407000-00011. PMID: 7930432.
3) Chrysanthos, N. & Anagnostopoulou, Evagelia & Daskalaki, Anna & Patsavela, Stamatia. (2015). Images of the Month. The American journal of gastroenterology. 110. 498. 10.1038/ajg.2014.251.
4) Chen WG, Zhu HT, Yang M, Xu GQ, Chen LH, Chen HT. Large heterotopic gastric mucosa and a concomitant diverticulum in the rectum: Clinical experience and endoscopic management. World J Gastroenterol 2018; 24(30): 3462-3468 [PMID: 30122884 DOI: 10.3748/wjg.v24.i30.3462]

Clinical Case Summary

Colorectal lymphomas are a rare cause of colonic neoplasia (0.2-0.6% malignant neoplasms of large bowel). Approximately 10% are primary colorectal lymphomas, while the rest correspond to colonic extension of systemic lymphoproliferative diseases.
We present the case of a 66-year-old woman with a history of rectum and pancreas adenocarcinoma (both in remission). During a follow-up CT, a thickening of the cecal pole was identified, with no adenopathy or other relevant findings (Photo1). The patient had no abdominal pain or B symptoms (night sweats, weight loss or fever).
The diagnosis was completed with a PET-CT that showed pathological uptake in the cecum (Photo2), so a colonoscopy was performed, which revealed a large polypoid lesion (30 mm) at the ileocecal level, with nodular areas with small ulcerations and no clear loss of the glandular pattern (Photo 3), from which multiple biopsies were taken.
Biopsies showed lymphoid proliferation with a ‘starry sky’ pattern, mitosis and apoptosis, and positive immunohistochemistry for CD45, CD20, CD10, BCL6, BCL2 and C-MYC, together with a high proliferation index (Ki-67 > 95%), all compatible with high-grade B-lymphoproliferative syndrome with Burkitt morphology (Photo 4).
Burkitt's lymphoma is a rare B-cell lymphoma (15% of GI lymphomas), associated with chromosomal translocation (8:14, 8:22 and 2:8) and overexpression of c-myc oncogene.
There are three clinical variants: endemic (common in Africa and associated with EBV and malaria), HIV-associated and sporadic (20%).
It is common in children and its most frequent symptoms are abdominal pain and weight loss, so diagnosis is often delayed. Although the yield of endoscopic biopsies is low (<20%), it is a key tool in its diagnosis, along with targeted biopsy of abdominal adenopathies.
Despite its aggressiveness, treatment with targeted chemotherapy achieves rates of more than 90%, and early diagnosis is essential to avoid complications and ensure adequate medical treatment.

References

- Photo 1: Thickening of the cecal pole seen in CT-Scan.
- Photo 2: Pathological uptake in the caecal area as seen on PET-CT Scan.
- Photo 3: Polypoid lesion in ileocecal area at colonoscopy
- Photo 4: Pathological anatomy of endoscopic biopsies: starry sky imaging and immunohistochemistry of Bcl-2 and C-myc

Clinical Case Summary

A 29-year-old man was admitted to the hospital with complaints of rectal tenesmus, a sensation of incomplete evacuation, diarrhea occurring 6-8 times daily, and occasional constipation. Digital rectal examination revealed a hard, immovable mass 5 cm from the anus, with an upper margin that could not be palpated. Laboratory tests showed a C-reactive protein (CRP) level of 4.68 mg/L and an erythrocyte sedimentation rate (ESR) of 28.0 mm/h. The tuberculosis-interferon gamma release assay and fecal occult blood test were positive. Computed tomography (CT) and rectal endoscopic ultrasound (EUS) showed a 6 cm mass in the lower rectum, thickened rectal walls with uneven enhancement, multiple enlarged lymph nodes and a solid perianal nodule measuring 5.0×4.0 mm. Endoscopy revealed irregular thickening of rectal wall, nodular lesions with erythema and erosion from 10 cm proximal to the anal canal, and intestinal stenosis with a fistula. Multiple biopsies from the colonoscopy showed chronic mucosal inflammation with hyperplastic glandular epithelial cells and mucus, but no malignancy was detected.
The patient received sequential treatments of metronidazole, mesalazine, and diagnostic antitubercular drugs, but showed no improvement. Finally, an endoscopic mucosal resection (EMR) was performed. Biopsy findings revealed crypt branching and distortion, reactive epithelial hyperplasia, a few chronic inflammatory cells in the lamina propria, and fibrosis of the submucosa, consistent with mucosal prolapse.
Rectal mucosal prolapse syndrome (RMPS) poses significant diagnostic challenges due to its overlapping clinical, endoscopic, and histopathological features with other rectal disorders, such as Crohn' disease, intestinal tuberculosis, and colorectal carcinoma^1-3. Detailed endoscopic evaluation and deep histopathological analysis is essential. In patients with a long history of abnormal defecation habits, RMPS should be considered in the differential diagnosis of rectal masses.

References

1. Hayasaka J, Hoteya S, Tomizawa K, et al. The Long-term Efficacy of Endoscopic Submucosal Dissection in the Treatment of Symptomatic Mucosal Prolapse Syndrome. Intern Med 2021;60:1005-1009.
2. Tang X, Han C, Sheng L, et al. Rectal mucosal prolapse with an emphasis on endoscopic ultrasound appearance. Dig Liver Dis 2021;53:427-433.
3. Chiang JM, Changchien CR, Chen JR. Solitary rectal ulcer syndrome: an endoscopic and histological presentation and literature review. Int J Colorectal Dis 2006;21:348-56.

Clinical Case Summary

Retrorectal epidermoid cystic tumors are rare and uncommon lesions that are usually asymptomatic. The appearance of symptoms such as pain or neurological disorders should raise suspicion of degeneration. We report the case of a 35-year-old woman who was found to have a renitent, painless mass compressing the posterior wall of the rectum while having a history of painful discomfort while sitting. The diagnosis was confirmed after the discovery of a well-circumscribed pre-sacral mass (76 × 70 mm) on computed tomography (CT) and MRI. She underwent posterior laparoscopy, and the excision of the encapsulated cystic mass was later confirmed to be an epidermoid cystic tumor. Finally, because of the risk of infection and malignant transformation, these tumors require a multidisciplinary approach to optimize the success of treatment.