Dear Madam, Thank you for using Healthcare Magic to receive an answer for your recent health events. Fibroids are almost invisible on histeroscopy. Submucosal ones may appear as an endometrial bulge in the uterine cavity (mucosa), as these are benign mases that do not infiltrate uterine layers. While intramural or subserosal fibroids are visible only on imaging modalities (MRI, CT scan or US). But in your case, MRI reports a very small fibroid, which makes it impossible to be detected on histeroscopy, in spite of its submucosal location. On and off bleeding following the procedure, is a consequence of the mild traumatic events in the uterine mucosa, as histeroscopy is considered somehow an invasive procedure, while dark spotting results from hemoglobin degradation due to trapped blood within uterus for a long time. Hope this was helpful. Please feel free to ask for any other sign or symptom concerning this situation. Thank you! Dr. Juarda