Endometriosis is a relatively common gynecological condition in women of reproductive age. The rectosigmoid region is the most commonly affected segment when the gastrointestinal tract is involved. A differential diagnosis of colorectal neoplasia is difficult because of the similar clinical, endoscopic, and radiology findings. A 42-year-old female presented with abdominal distention and was subsequently diagnosed with a large bowel obstruction in the rectum. A temporary colostomy was performed, and endoscopy revealed a rectal mass obstructing the rectum. The biopsy showed normal mucosa, and it was difficult to exclude rectal malignancies even after the imaging workup. Endoscopic ultrasound demonstrated a hypoechoic lesion below the rectal mucosa, and fine needle aspiration confirmed the diagnosis of bowel endometriosis. Bowel endometriosis is a challenging diagnosis. Endoscopic ultrasound-guided fine-needle aspiration is useful for acquiring adequate samples for histological confirmation and a definitive diagnosis of bowel endometriosis.

Objective: To evaluate the antioxidant, antibacterial and bacterial cell agglutination activities of the hexane (Hex) and 70% ethanol (70% EtOH) extracts of two species of red seaweeds Pterocladiella capillacea (P. capillacea) and Osmundaria obtusiloba. Methods: In vitro antioxidant activity was determined by DPPH radical scavenging assay, ferric-reducing antioxidant power assay, ferrous ion chelating assay, β-carotene bleaching assay and total phenolic content quantification. Antimicrobial activity was tested using the method of disc diffusion on Mueller-Hinton medium. The ability of algal extracts to agglutinate bacterial cells was also tested. Results: The 70% EtOH extract of the two algae showed the highest values of total phenolic content compared to the Hex extract. The results of DPPH for both extracts (Hex, 70% EtOH) of Osmundaria obtusiloba (43.46% and 99.47%) were higher than those of P. capillacea (33.04% and 40.81%) at a concentration of 1. 000 μg/mL. As for the ferrous ion chelating, there was an opposite behavior, extracts of P. capillacea had a higher activity. The extracts showed a low ferric-reducing antioxidant power, with optical density ranging from 0.054 to 0.180. Antioxidant activities of all extracts evaluated for β-carotene bleaching were above 40%. There was no antibacterial activity against bacterial strains tested. However, the extracts of both species were able to agglutinate bacterial Gram positive cells of Staphylococcus aureus and Gram negative cells of Escherichia coli, multidrug-resistant Salmonella and Vibrio harveyi. Conclusions: This is the first report of the interaction between these algal extracts, rich in natural compounds with antioxidant potential, and Gram positive and Gram negative bacterial cells.