E1140. Calcified Sister Mary Joseph Nodule as the Presenting Complaint of Advanced Low-Grade Serous Ovarian Cancer
  1. Luhe Yang; Department of Medical Imaging, Royal University of Hospital; Faculty of Medicine, University of Saskatchewan
  2. Marilyn Kinloch; Department of Pathology and Laboratory Medicine, Royal University Hospital; Faculty of Medicine, University of Saskatchewan
  3. Vickie Martin; Division of Oncology, Department of Gynecology, Royal University Hospital; Faculty of Medicine, University of Saskatchewan
  4. Farid Rashidi; Department of Medical Imaging, Royal University of Hospital; Faculty of Medicine, University of Saskatchewan
Sister Mary Joseph nodule (SMJN) refers to a secondary metastatic lesion of the umbilicus. The most common primary sites of SMJN are the stomach (18%-28%), ovary (8%-24%), colon (10%-18%), and pancreas (7%-15%), with unknown primary in 15%-29% of cases [1,2]. Approximately 60% of umbilical masses can be benign, and as a result a malignant umbilical nodule may be present for several months before the diagnosis of malignancy is established. This is not ideal since SMJN heralds advanced stages of intra-abdominal malignancy, with mean life expectancy of only 17.6 to 21 months despite aggressive multimodal treatment [3]. Therefore, there is significant value in increasing radiologists’ awareness of an atypical appearing SMJN.

Educational Goals / Teaching Points
A healthy 38-year-old woman, who presented with a hard umbilical mass with no other symptoms and signs, was proven to have low-grade serous ovarian cancer on subsequent imaging and histopathology work-up. Although heterogeneously calcified umbilical masses in high-grade serous ovarian cancer has been reported by authors such as Inanir and Oksuzoglu [4], and Evans et al. [5], a densely calcified umbilical mass is novel, particularly in low-grade serous ovarian cancer. This emphasizes the importance of increased imaging awareness to seemingly benign findings such as a densely calcified umbilical mass as a sign of advanced intra-abdominal and pelvic malignancy.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Computed tomography scan of the abdomen and pelvis confirmed a lobulated and completely calcified mass within the umbilicus. A well-defined 0.9 cm calcification was noted along the lower aspect of the greater omentum. Non-specific tiny calcifications were noted in posterior cul-de-sac. Based on these findings, the diagnosis of an omphalolith was primarily reported. The patient underwent a local excision and histopathology, which showed low-grade serous adenocarcinoma in the subepithelial fibrous tissue characterized by monomorphic nuclei and abundant dark purple, psammomatous calcifications, indicative of metastatic low-grade serous carcinoma of ovarian origin. This promptly led to an uncomplicated total abdominal hysterectomy and bilateral salpingo-oophorectomy, which noted small ovaries with endosalpingiosis, suspicious appearing nodules in the omentum and bladder serosa, and multiple nodules of the rectosigmoid mesentery and proper, with some that were deeply embedded in the retro-uterine cul-de-sac. On pathological analysis of the surgical specimens, low-grade serous carcinoma was identified in both ovaries, bladder peritoneum, rectal sigmoid nodule, and uterine cul-de-sac. Final staging was determined to be pT3c pNX pM1, corresponding to International Federation of Gynecology and Obstetrics (FIGO) stage IV ovarian cancer.

Though a densely calcified umbilical mass with no associated soft tissue component is atypical for a metastatic umbilical implant, consideration of metastatic disease in the imaging differential diagnosis is crucial in avoiding delays of histological identification of the primary lesion and improving patient outcome.