Microscopic heterotopic extraovarian sex cord-stromal proliferations were first reported in the literature in 2015 by McCluggege. Afterwards, few similar cases have been described. Herein, we report the fourteenth case of microscopic heterotopic sex cord-stromal proliferation and the third case sited in the pelvic peritoneum. The clinical history of these rare cases suggests their benign nature. Knowledge of this histological pattern is important for differential diagnoses such as malignant pathologies and metastatic diseases.

OBJECTIVE: Does endometriosis prevalence differ in patients with obstructive Müllerian anomalies (OMA) versus those with nonobstructive Müllerian anomalies (NOMA), and in patients with NOMA versus those without Müllerian anomalies?
CONCLUSIONS: The quantitative synthesis of published data demonstrates a substantially increased prevalence of endometriosis in patients with OMA compared with those with NOMA, and a similar prevalence in patients with NOMA and those without Müllerian anomalies.
BACKGROUND: The pathogenesis of endometriosis has not been definitively clarified yet. A higher prevalence of endometriosis in patients with OMA than in those with NOMA would support the retrograde menstruation (RM)/implantation theory, whereas a higher prevalence of endometriosis in the NOMA group than in the group without Müllerian anomalies would support the embryonic remnants/celomic metaplasia hypothesis.
METHODS: This systematic review with meta-analysis was restricted to full-length, English-language articles published in peer-reviewed journals between 1980 and 2023. The PubMed and EMBASE databases were searched using the keyword \'endometriosis\' in combination with \'Müllerian anomalies\', \'obstructive Müllerian anomalies\', \'female genital malformations\', \'retrograde menstruation\', \'infertility\', \'pelvic pain\', and \'classification\'. References from relevant publications were screened, and PubMed\'s \'similar articles\' and \'cited by\' functions were used.
METHODS: Studies were selected if they reported the prevalence of surgically confirmed endometriosis in either individuals with OMA compared to those with NOMA, or patients with NOMA compared to those without Müllerian anomalies. Cohort and case-control studies and case series were deemed eligible for inclusion. Noncomparative studies, studies not reporting both the number of individuals with endometriosis and the total number of those with Müllerian anomalies or with other gynecological conditions, those including exclusively data on patients with absent or uncertain menstrual function (e.g. complete Müllerian agenesis category), or with imperforate hymen were excluded. Two reviewers independently abstracted data. The risk of bias was assessed with the Risk of Bias In Non-randomized Studies of Exposures tool. The overall certainty of the evidence was graded according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) guidelines.
RESULTS: Seven retrospective studies were included. The overall mean estimate of endometriosis prevalence was 47% (95% CI, 36-58%) in patients with OMA, and 19% (95% CI, 15-24%) in patients with NOMA, with a common odds ratio (OR) of 4.72 (95% CI, 2.54-8.77). The overall mean estimate of endometriosis prevalence in patients with NOMA was 23% (95% CI, 20-27%), and that in patients without Müllerian anomalies was 21% (95% CI, 20-22%), with a common OR of 0.95 (95% CI, 0.57-1.58). The overall certainty of the evidence according to GRADE guidelines was judged as low for both comparisons.
CONCLUSIONS: Some NOMA subtypes may create a partial obstacle to menstrual efflux and/or generate dysfunctional myometrial contractions that favor transtubal reflux, thus increasing the risk of endometriosis and limiting the difference between OMA and NOMA. As infertility and pelvic pain are strongly associated with endometriosis, women with these symptoms are inappropriate controls. Confounding by indication could explain the lack of difference in endometriosis prevalence between patients with NOMA and those without Müllerian anomalies.
CONCLUSIONS: The results of this meta-analysis support the validity of the RM theory but do not definitively rule out alternative hypotheses. Thus, RM may be considered the initiator for the development of endometriotic lesions, while not excluding the contribution of both inheritable and tissue-specific genetic and epigenetic modifications as disease-promoting factors.
BACKGROUND: No funding was received for this review. P.Ve. is a member of the Editorial Board of Human Reproduction Open, the Journal of Obstetrics and Gynaecology Canada, and the International Editorial Board of Acta Obstetricia et Gynecologica Scandinavica; has received royalties from Wolters Kluwer for chapters on endometriosis management in the clinical decision support resource UpToDate; and maintains both a public and private gynecological practice. E.S. discloses payments from Ferring for research grants and honoraria from Merck-Serono for lectures. All other authors declare they have no conflict of interest.
BACKGROUND: N/A.

Foci of spindle cell proliferation of the thyroid gland have been documented in adenoma and carcinoma, but not much in multinodular goiter. We report a case of spindle cell proliferation detected in multinodular goiter in a 61-year-old female. Histological examination revealed foci of solid area around the normal thyroid follicles. There were two components in this solid area; the first one was composed of epithelial cells with small bland ovoid nuclei and the second one with spindle cells with short spindle-shaped nuclei. Immunohistochemical analysis revealed that the spindle cells were positive for thyroid transcription factor (TTF)-1, Vimentin, CK (AE1/AE3), and negative for p63, etc. The cells with ovoid nuclei had more abundant CK (AE1/AE3) immunoreactivity than those with short spindle-shaped nuclei. In addition, the transition between these two cell types was clearly identified. We hypothesized that this area represented embryonic remnant of developing thyroid gland and therefore evaluated histological features of developing fetal thyroid but this lesion by no means simulated histological features of any developing stages of fetal thyroid gland. The spindle cell foci of thyroid gland could possibly arise from epithelial-mesenchymal transformation of thyroid follicular epithelium in this thyroid gland but it awaits further investigations for clarification.

Objective: To review the diagnostic methodology in pediatric patients with obstruction of the lower third of the esophagus as well as minimally invasive therapeutic options. Materials and Methods: Retrospective study carried out reviewing records of children with esophageal obstruction diagnostic, from 2000 to 2018. They were divided into Group I stenosis secondary to reflux; Group II achalasia; and Group III embryonic remnants. Results: Thirty-three patients. Group I: 7; esophageal barium swallow irregular stenosis of the distal third and endoscopy irregular stenosis in 7. Treated with laparoscopic fundoplication 2, Collis Nissen 5. Group II: 22 patients, age X = 11.55 years. All with dysphagia and symmetrical stenosis of esophagogastric junction. Fifteen underwent manometry and all underwent intraoperative endoscopy. All had laparoscopic myotomy, with 2 perforations and no conversions, 2 patients had subsequent dysphagia to solids, and they did not need esophageal dilatation. Group III: 4 patients, stenosis was above esophagogastric junction. On endoscopy, inflammation was present in all 3 with irregular esophagogastric junction and difficulty passing endoscope. Three patients underwent laparoscopic resection and anastomosis. One patient leaked and developed a fistula. One patient has not been operated upon as yet. Conclusions: In those patients, the best surgical option depends upon the diagnosis. Esophageal barium studies and endoscopy allow discerning among them.

The urachus is an embryonic remnant that usually involutes before birth. Abnormal persistence of this structure can lead to infectious or neoplastic complications later in life. We report a case of an 84-year-old man that presented with a urachal complex mass which, after proper investigation, revealed to be a urachal abscess. Urachal abscesses are rare and usually occur in severe infections. Urachal abscesses can be indistinguishable from urachus carcinoma on imaging studies. This article reviews the clinical and imaging aspects of urachal abscess and carcinoma and possible differentiating elements in imaging. However, definitive diagnosis usually depends on a biopsy or fluid aspiration.

The objective of this study is to better understand embryonic vitelline vascular remnants in the umbilical cord, to assess their prevalence, to categorize their morphology, and then finally to describe and assess inflammation arising from these structures. During routine placental sign out, the author noted the presence or absence of vitelline vessel remnants for 1 year; when present, he assessed their histologic patterns and noted whether there were neutrophils marginating from the remnants and into the adjacent Wharton\'s jelly and whether there was any other evidence of amniotic fluid infection in sections of placental disc, membranes, or cord. All cord sections with vitelline vessel remnants were immunostained for CD15 to document any infiltrates, to highlight patterns of infiltration, and to evaluate whether mild cases of umbilical phlebitis were associated with these lesions and were at risk of being missed. Vitelline vessel remnants were present in 4.2% of placentas examined. There were 5 vitelline vessel remnant histologic patterns identified providing insight into the vitelline vessel circulation. Funisitis, primarily neutrophilic, arising from vitelline vessel remnants was present in 70.3% of the 37 cords with vitelline vessel remnants. The presence of vitelline vessel remnant funisitis documents continued active circulation in these vascular structures, and vitelline vessel remnant funisitis was associated with the presence of other placental histological evidence of amniotic fluid infection in 53.8% of cases. The author also reviews normal embryology and the pathology of vitelline vessel remnants.