This study presented a patient with dermatomyositis/myasthenia gravis accompanied by undiagnosed Müllerian duct anomaly and bilaterally undescended ovaries. This extremely rare case has not been reported before.
Maldescended single ovary is rare, and the occurrence of bilateral undescended ovaries is extremely rare. According to a mini-review by Jennifer E. Dietrich, the prevalence of maldescended ovaries is 0.3–2%. Seventy-three percent of the reported cases have concomitant Müllerian duct anomalies. The prevalence of bilateral undescended ovaries is 23% with an absolute count of 6 patients as noted in the mini-review [2]. Similar to other cases, an elongated fallopian tube related to the undescended ovaries was detected in this case [3, 4]. Migration disorders can occur both in the ovaries and uterus, resulting in undescended ovaries and abnormal fusion of the uterus, respectively [5].
A didelphys uterus is formed when a fusion defect of the Müllerian ducts occurs. According to ESHRE/ESGE classification, there is a complete septate uterus with a hypoplastic dual cervix and a normal nonseptate vagina [6]. Our case had a didelphys uterus (Fig. 3) with undescended ovaries (Figs. 1, 2). Her medical history showed normal feminine appearance and menstruation with 3 years of infertility. No coexistent urothelial abnormality was found in this case, although according to other studies urothelial abnormalities are usually seen with Müllerian duct anomalies [4, 7].
The association between neuromuscular junction disorders and/or paraneoplastic syndromes is another interesting point of this case report.
Dermatomyositis coexistent with myasthenia gravis disease is a rare condition [8, 9]. According to Naohiro Uchio, most of the cases of dermatomyositis coexistent with myasthenia gravis had a history of thymoma (about 7 of 10 cases) [9]. The rare coexistence of dermatomyositis and myasthenia gravis is reported to be associated with immune-related adverse events clinically correlated with cardiac involvement and elevated serum CK levels [10, 11]. Association of Müllerian duct anomaly with myasthenia gravis was first reported in SAMUEL ARIAD report who presented a patient with malignant mixed müllerian tumor (MMMT) with sarcomatous differentiation and neuromuscular disorder as a result of the production of autoantibodies against nicotinic acetylcholine receptors in the nerve end-plate, although the diagnosis was made after abdominal metastasis [12].
In our case, dermatomyositis/myasthenia gravis coexistence with Müllerian duct anomaly and undescended ovaries was diagnosed with a history of type B thymoma resection, exertional dyspnea, and elevated creatinine kinase (CK) levels. At the moment we don’t find any obvious tumoral growth in the Müllerian duct, but regarding the probability of non-overt and subclinical paraneoplastic features of the patient’s condition, abdominopelvic sonographic follow-up surveillance was highly recommended.
This case report is written with the patient’s conscious permission, and all personal information is kept confidential.