Deciduoma, a Large Intrauterine Mass of Deciduosis

► intrauterine mass ► placenta ► deciduoma ► ectopic uterine tissue

Deciduosis is the presence of ectopic decidual tissue outside the uterus, pelvic, or abdominal organs usually associated with pregnancy. It usually presents as smaller lesions but can be larger vascular lesions . Typically, these masses are detected incidentally during operative procedures. Our patient was referred at 14 weeks for a large intrauterine mass detected on ultrasound examination that was initially thought to be an acardiac twin. The mass was highly vascularized. However, since the patient was asymptomatic, she strongly desired to continue the pregnancy. The pregnancy was followed closely from 14 to 39 weeks with serial ultrasound examinations. The vascularity was documented to diminish overtime and the mass appeared to convolute as well. Due to the decrease in vascularity of the mass, the patient was allowed spontaneous vaginal delivery at term. Following delivery of the fetus and the placenta, the mass was easily extracted manually without any complications. received May 4, 2019 accepted after revision May 14, 2019 DOI https://doi.org/ 10.1055/s-0039-1697647. ISSN 2157-6998. Copyright © 2019 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA. Tel: +1(212) 584-4662. THIEME Case Report e337 Published online: 2019-11-14 suspected to be malignant on further workup she would have the option of pregnancy termination. The patient declined to pregnancy termination irrespective of the diagnosis. A mag- netic resonance imaging (MRI) was ordered, and the patient was subsequently referred for a consultation with the gyne- cologic services for assessment of the tumor. An MRI at 18 5/7 weeks reported a soft tissue mass of 1.6 /C22.0 /C24.9 cm, eccentric and crescentic shaped with dif- ferential diagnosis of a “Stuck Twin syndrome ” with demise of the presenting stuck twin. At 19 3/7 weeks, on a repeat obstetrical ultrasound, the fluid surrounding the mass and the vascularity were signi ficantly reduced. The mass contin- ued to have minimal arterial circulation with a pulse rate consistent with the maternal heart rate. Ultrasound examinations were initially repeated every month. At 21 3/7 weeks, the mass stayed stable in size, measuring 4.36 /C22.00 /C23.26 cm and, at 25 3/7 weeks, it was essentially unchanged measuring 4.7 /C22.6 /C21.8 cm. Due to the stable size of the mass, as well as signi ficantly reduced vascularity, the patient was reexamined at 33 5/7 weeks and the mass had reduced in size measuring 3.6 /C22.2 /C23 cm. Over time, the vascularity was documented to de- crease with minimal blood flow. The mass stayed adherent to the lower portion of the posterior uterine wall. At 39 4/7 weeks, the patient experienced spontaneous labor and underwent a normal vaginal delivery. Following the delivery of the baby, the uterine cavity was explored and, with complete ease, the mass was manually extracted in full, with no additional blood loss. It was a smooth soft spongy mass with no raw edges ( ►Fig. 3). On pathology, the mass measured 7.5 /C24.7 /C22.6 cm and was described as an ovoid, membra- nous, dark red, soft tissue with a hemorrhagic surface. On the Fig. 1 Increased vascularity within the Intrauterine Mass at 14 4/7 weeks ’ gestation. Fig. 2 Intrauterine mass surrounded by fluid, at 14 4/7 weeks ’ gestation. American Journal of Perinatology Reports Vol. 9 No. 4/2019 Features of Deciduoma Dasanie338 final histopathologic diagnosis, the mass was reported as deciduosis (►Fig. 4). Three weeks after delivery a postpartum ultrasound was performed which was normal. Findings indi- cated anteverted normal appearing midline uterus and cervix. Endometrial stripe was normal. Ovaries were normal bilater- ally with no cysts or masses. There was no evidence of the previously observed lower uterine mass.

Ectopic deciduosis has been defined as decidual tissue found in an extrauterine location during a pregnancy. There are various theories on the pathogenesis of deciduosis. It has been sug- gested that progesterone can induce ectopic decidua, a revers- ible phenomenon. 6,7 In association with pregnancy, the ectopic decidual cells have been reported in the fallopian tube, ovaries, uterine serosa, cervix, and vagina, as well as outside the genital tract including the peritoneum, omentum, appendix, and lymph nodes but not intrauterine.4,7 The lesions are described as white nodules less than 1 cm in diameter that may coalesce or be isolated. 7 Ectopic decidua is usually an incidental finding, detected during surgical procedures, which include Cesarean sections, postpartum tubal ligations, and appendectomies.7 Typically asymptomatic, deciduosis can present with clinical symptoms of shortness of breath, hemop- tysis, pneumothorax, progressive anemia, pelvic pain, and risk of infections depending on the site. Rarely, complications, such as massive intra-abdominal bleeding have been reported. 5 Though the lesions are typically described in mm, larger lesions in the cervix and the omentum have been reported. The cervical lesions have been described as large masses with the largest reported being 8 cm. 4 In the omentum, the lesions can be large as well. When the mass is large, it is frequently mistaken for malignancy and requires histopathology for final diagnosis. 2,4 Omental and peritoneal lesions are more common and with increasing duration of pregnancy regres- sive changes have been reported. 8 To our knowledge, there are no reported cases of intrauter- ine deciduosis during the course of a normal pregnancy. In our case, we had the advantage of following the lesion longitudi- nally from the end of the first trimester until delivery at term. To our surprise, the vascularity, as well as the size of the mass, was seen to reduce remarkably by the third trimester, making it highly unlikely that we were dealing with a malignant tumor. At delivery we were prepared for an adherent mass and postpartum hemorrhage. However, the entire mass was easily extracted manually, without any complications. Fortunately, in our case, in spite of the lesion being large, the patient did not experience any episode of heavy bleeding antenatally or during the time of delivery. Perhaps, since the vascularity regressed overtime, the delivery was uncomplicated.

In conclusion, based on our case and those reported in the literature, we believe that there are two separate entities of ectopic deciduosis, diffuse deciduosis with smaller lesions and the larger vascular mass lesions. We propose to classify ectopic deciduosis into two categories, as benign diffuse ectopic deciduosis which is typically asymptomatic, and a deciduoma which is a large vascular lesion with potential for hemorrhage. By categorizing the larger vascular lesions as deciduoma, the lesion may be accurately diagnosed prena- tally more frequently, and it could help the obstetrician prepare for the possible hemorrhagic complications. It would also guide the obstetrician in continuing with expectant management, with the hope of reduction in vascularity and size of the lesion as the pregnancy progresses. Conflicts of interest None.

1 Walker A. Der bau der Eihaeute bei Graviditatis abdominalis. Virch Arch Path Anat. 1887;197:72 –99 Fig. 3 Mass extracted during delivery, measured 7.5 /C24.7 /C22.6 cm. Fig. 4 Histopathology of the intrauterine mass. American Journal of Perinatology Reports Vol. 9 No. 4/2019 Features of Deciduoma Dasani e339 2 Markou GA, Goubin-Versini I, Carbunaru OM, Karatzios C, Muray JM, Fysekidis M. Macroscopic deciduosis in pregnancy is finally a common entity. Eur J Obstet Gynecol Reprod Biol 2016;197:54–58 3 Kinra P, Sen A, Sharma JC. Ectopic decidual reaction: a case report. Med J Armed Forces India 2006;62(03):280 –281 4 Gornall AS, Naftalin NJ, Brown LJ, Konje JC. Massive necrosis of cervical ectopic decidua presenting in labour. BJOG 2000;107 (04):573–575 5 Lüdders DW, Henke RP , Saba M, Raddatz L, Soliman A, Malik E. Severe maternal pre- and postpartum intra-abdominal bleeding due to deciduosis. Geburtshilfe Frauenheilkd 2015;75(03):259–262 6 Ellis CL, Maleki Z, Ali SZ. Ectopic decidua in abdominal washings found intraoperatively at cesarean section. Diagn Cytopathol 2010; 38(10):740–741 7 Shukla S, Pujani M, Singh SK. Ectopic decidual reaction mimicking peritoneal tubercles: a report of three cases. Indian J Pathol Microbiol 2008;51(04):519 –520 8 Büttner A, Bässler R, Theele C. Pregnancy-associated ectopic decidua (deciduosis) of the greater omentum. An analysis of 60 biopsies with cases of fibrosing deciduosis and leiomyoma- tosis peritonealis disseminata. Pathol Res Pract 1993;189(03): 352–359 American Journal of Perinatology Reports Vol. 9 No. 4/2019 Features of Deciduoma Dasanie340