Abstract
109
Introduction: A 42-year-old woman was referred to us after suffering intermittent abdominal pain for 10 months. Ultrasonography showed a mass on the left ovary. Her Ca125 was elevated to 1154 U / ml (normal reference < 35 U / ml). An 18F-FDG PET/CT was employed to assess the disease activity and stage the extent of the disease. The maximum intensity projection image (Fig 1, MIP, A) revealed two foci of increased tracer uptake in the left chest (dotted head), the right lower abdomen (yellow arrow). On axial PET images, these foci corresponded to left hilar lymph node (B, the right upper row, dotted head), the right ovary (C, the right midrow, yellow arrow) on the CT and fusion images. In addition, a large solid mass approximately 6.2 x 4.2 cm in size with non-uniform density and peripherally abnormally uptake of FDG was seen in the region of left pelvis (C, red arrowheads). Unexpectedly, there were numerous small sclerotic lesions in the vertebras without obvious FDG uptake (D, the right lower row, blue thin arrows). The findings were suggestive of a pelvic malignancy, likely ovarian cancer, with multiple metastases. Further 18F-NaF PET/CT scan was performed to evaluate the extent of the sclerotic lesions. The MIP image (Fig 2, A) showed abnormally increased activity in the head (B, small arrow), and left femur (C, curved arrow). On the axial images, the elevated NaF activity in the frontal bone (B, small arrow), distal femur and patella (C, curved arrow) with increased NaF activity. In addition, the ribs (not shown), the vertebras (D, blue thin arrows) and pelvic (not shown) also showed increased activity, on which FDG PET/CT had shown normal activity. The presentation was unlike osteoblastic metastases from ovarian cancer. The patient then underwent ovarian tumor resection. The pathology examination (Fig 3, HE, x200) from the surgical specimen in the left ovary revealed an ovarian endometriosis. Six months after surgery, the patient did not show any abdominal pain. The combination of medical history and imaging characteristic, and the widespread sclerotic lesions were suggestive of osteopoikilosis (OPK). OPK is a rare bone dysplasia with asymptomatic or nonspecific bone pain. It is characterized by the presence of multiple and often symmetrical foci of dense spots in the cancellous bones which usually found incidentally. Several clinical abnormalities associated with OPK have been reported, including ankylosing spondylitis, rheumatoid arthritis, synovial chondromatosis, cutaneous lesions and prostate cancer. Bone scintigraphy and18F-FDG PET/CT in this disease were usually showed normally or slightly uptake. Our case indicates that ovarian endometriosis may associate with OPK as well as bone lesions activities of this disease on 18F-NaF PET/CT showing asymmetrically.