Giant Villous Adenoma of the Rectum With Prolapse: Case Report

Abstract

Colorectal polyps, frequently adenomas, are common in older adults, with villous adenomas being a notable subset due to their potential for significant malignancy risk. This case report highlights a rare instance of a giant villous adenoma in a 79-year-old female patient, challenging in both diagnosis and treatment. The patient, with a history of untreated essential arterial hypertension, was hospitalized for severe anemia following a massive rectal hemorrhage. An irreducible, prolapsed rectal mass was evident upon examination, and further investigations, including rectoscopy and abdominopelvic computed tomography scan, confirmed a villous adenoma with severe dysplasia. Given the tumor's substantial size, circumferential nature, and proximity to the dentate line, an abdominoperineal resection using the Miles technique was performed. The histopathological examination post-surgery confirmed the presence of a villous adenoma with high-grade epithelial neoplasia and localized areas of well-differentiated tubular adenocarcinoma. This case underscores the diagnostic and management complexities of large villous adenomas, emphasizing the need for meticulous surgical decision-making to ensure oncological safety and patient welfare, particularly when conservative resection may be inadequate.

Keywords: emergency gastroenterology and endoscopy; giant villous adenoma; inferior digestive hemorrhage; proctology; villous tumor.

Figure 1. Prolapsed rectal tumor: clinical presentation

A photograph showing the prolapsed rectal tumor as observed during physical examination.

Figure 2. Computed tomography scan of the anal-rectosigmoid mass

Coronal view showing the anal-rectosigmoid mass measuring 6.8 cm × 5.3 cm, with invasion into perirectal structures and multiple local-regional adenopathies. Degenerative disc and vertebral changes are highlighted with arrows indicating the tumor location.

Figure 3. Resected specimen of the rectum with intraluminal vegetative tumor

A photograph of the longitudinally cut specimen of the rectum, displaying the intraluminal vegetative tumor.

Figure 4. Microscopic evaluation of the villous adenoma

A microscopic view of the villous adenoma, detailing the general histopathological features.

Figure 5. Histopathology: fibrous septa with tumor epithelium

A microscopic view showing delicate fibrous septa covered by tumor epithelium without significant nuclear pleomorphism (hematoxylin and eosin stain, 100× magnification).

Figure 6. Histopathology: complex tumor architecture

Microscopic evaluation of the tumor showing more complex architecture with irregular glands, without significant pleomorphism and no tumor invasion (hematoxylin and eosin stain, 100× magnification).

Figure 7. Histopathology: epithelial proliferation with moderate nuclear atypia

Microscopic image showing epithelial proliferation of columnar cells with moderate nuclear atypia, displaying a glandular and alveolar pattern (hematoxylin and eosin stain, 20× magnification).

Figure 8. Histopathology: glandular architecture and stromal infiltration

Microscopic view revealing complex glandular architecture and stromal infiltration by small clusters of atypical cells in an area with a desmoplastic stromal response, with no invasion into the muscularis mucosa or submucosa (hematoxylin and eosin stain, 20× magnification).

Figure 9. Histopathology: no muscularis mucosa invasion

Microscopic evaluation showing no invasion of the muscularis mucosa (smooth muscle actin coloration, 100× magnification).

Figure 10. Immunohistochemistry: Ki67 cancer-marker evaluation

Microscopic view with immunohistochemistry showing relatively rare tumor nuclei positive for the Ki67 cancer marker (200× magnification).

Figure 11. Immunohistochemistry: microsatellite instability markers evaluation

Microscopic evaluation and immunohistochemistry showing tumor cells with various levels of positivity for microsatellite instability markers, indicating no microsatellite instability within the tumor.

Figure 12. Immunohistochemistry: comprehensive microsatellite instability analysis

Microscopic view with immunohistochemistry showing no microsatellite instability within the tumor. Tumor markers used include MutL homolog 1 (MLH1), postmeiotic segregation increased 2 (PMS2), MutS homolog 2 (MSH2), MutS homolog 6 (MSH6), and adenomatous polyposis coli (APC; 200× magnification).