Giant primary ovarian leiomyoma with cystic degeneration and calcification complicated by post-surgical acute pulmonary embolism in a 23-year-old nulligravida: A Case report

Leiomyomas of primary ovarian origin are rare, benign, smooth muscle neoplasm constituting just 0.5-1% of the entire tumours of the ovary. They are often of small size, unilateral and occur predominantly in premenopausal women, usually diagnosed incidentally, aided by examination of the pelvis, post-surgery histopathological evaluation and confirmed by immunohistochemical staining. Additionally, primary ovarian leiomyoma of this size (with the greatest diameter of 29.5cm) has not been reported in the literature. It is not uncommon for large pelvic tumours to be associated with venous thromboembolic events (VTE). We hereby present a case of a 23-year-old nulliparous woman who presented with complaints of abdominal pain and swelling. Clinical examination revealed an abdominal mass of 34 weeks’ size. Abdominal ultrasonography showed an intra-abdominal mass that extended to the pelvis and a misdiagnosis of giant uterine leiomyoma was made. On laparotomy, a huge, right, well-encapsulated ovarian mass with a smooth surface was seen. Histopathological and immunohistochemical staining with desmin and vimentin confirmed it to be a giant primary ovarian leiomyoma with cystic degeneration and calcification. Additionally, the patient developed sudden onset of chest pain and breathlessness a day post-surgery for which urgent computed tomography pulmonary angiogram (CTPA) confirmed pulmonary embolism (segmental and post segmental regions bilaterally) and cardiomegaly. She was placed on low molecular weight heparin (Clexane) and oral warfarin which she responded well to. Indeed, primary ovarian leiomyoma should be considered an important differential in primary solid ovarian and pelvic tumours. Also, in large or giant pelvic neoplasms, anticoagulant prophylaxis should be considered to prevent untoward pulmonary embolism and its possible fatal outcomes.

原发性卵巢平滑肌瘤（primary ovarian leiomyomas）是一种罕见的良性平滑肌肿瘤，仅占卵巢全部肿瘤的0.5%~1%。该类肿瘤通常体积较小，多为单侧性，好发于绝经前女性，大多通过盆腔检查、术后组织病理学评估偶然确诊，并经免疫组织化学染色证实。此外，最大直径达29.5cm的此类原发性卵巢平滑肌瘤在既往文献中未见报道。大型盆腔肿瘤常与静脉血栓栓塞症（venous thromboembolic events, VTE）相关。本文报告1例23岁未生育女性，因腹痛及腹胀就诊。体格检查发现腹部肿块大小相当于妊娠34周。腹部超声显示腹腔内肿块延伸至盆腔，最初被误诊为巨大子宫平滑肌瘤。剖腹探查术中可见右侧巨大、包膜完整、表面光滑的卵巢肿块。经结蛋白（desmin）和波形蛋白（vimentin）免疫组织化学染色及组织病理学检查，证实其为伴囊性变与钙化的巨大原发性卵巢平滑肌瘤。术后次日患者突发胸痛、呼吸困难，急诊计算机断层扫描肺血管造影（computed tomography pulmonary angiogram, CTPA）证实双侧肺段及亚段肺栓塞，且合并心脏增大。予低分子肝素（Clexane）及口服华法林治疗后患者病情好转。诚然，原发性卵巢平滑肌瘤应作为卵巢原发性实性及盆腔肿瘤的重要鉴别诊断之一。此外，对于大型或巨大盆腔肿瘤，应考虑抗凝预防以避免致命性肺栓塞及其不良后果。