Objective To investigate the computed tomography (CT) features of primary liver leiomyosarcoma (PHLMS).

Methods The retrospective and descriptive study was conducted. The clinical and imaging data of 10 patients with PHLMS who were admitted to 4 medical centers including 3 cases in Wenzhou Central Hospital, 3 cases in the Second Affiliated Hospital of Wenzhou Medical University, 2 cases in Wenzhou People's Hospital and 2 cases in Yueqing People's Hospital from January 2011 to December 2020 were collected. There were 5 males and 5 females, aged from 41 to 83 years, with a median age of 55 years. All 10 patients underwent abdominal CT examination. Observation indicators: (1) CT features; (2) treatment and pathological examination; (3) follow-up and survival. Follow-up using postoperative outpatient or inpatient examination to detect patient survival was conducted. Patients underwent imaging examination to detect tumor recurrence. Follow-up was up to December 2020. Measurement data with skewed distribution were represented as M (range). Count data were described as absolute numbers.

Results (1) CT features: results of CT examination showed that each of the 10 patients had only one single tumor, including 3 cases with tumor on the left lobe of liver and 7 cases with tumor on the right lobe of liver. The tumor diameter of the 10 patients was 8.0 cm(range, 4.5-13.5 cm). Results of plain CT scan of 10 patients showed that 7 cases had tumor in expansive growth as round or oval, with clear boundaries and the tumor parenchyma showing low-density signals and patchy lower density area can be seen in the center, and 3 cases had tumor in infiltrative growth as patchy, with unclear boundaries and the tumor parenchyma showing iso-density signals. The CT scan value of 10 patients was 40 HU(range, 23-47 HU). Results of enhanced CT scan at arterial phase of the 7 cases with tumor in expansive growth showed that 3 cases undergoing tumor parenchyma with uneven mild enhancement signals, 3 cases undergoing tumor parenchyma with uneven moderate enhancement signals and 1 case undergoing tumor parenchyma with uneven significant enhancement signal. The CT scan value of 7 cases was 68 HU(range, 62-88 HU). Results of enhanced CT scan at arterial phase of the 3 cases with tumor in infiltrative growth showed that the peripheral region had high signal than the central region. The CT scan value of 3 cases was 73 HU(range, 67-90 HU). Results of enhanced CT scan at portal vein phase in the 7 cases with tumor in expansive growth showed that the tumor parenchyma showing continuous and progressive mild and moderate enhancement with uneven density, and the CT scan value was 63 HU(range, 55-78 HU). Of the 7 cases, 3 cases showed the enhancement range of tumor parenchyma with the trend of fusion and filling, and 4 cases showed small patchy or nodular enhancement and grid like enhancement in the center and periphery of the tumor. Results of enhanced CT scan at portal vein phase in the 3 cases with tumor in infiltrative growth showed that the enhancement withdrew, the density was uneven, and the CT scan value was 58 HU(range, 50-62 HU). Results of enhanced CT scan at delayed phase in 10 patients showed that the enhancement in the tumor withdrew slowly, and the CT scan value was 53 HU(range, 50-60 HU). Of the 10 patients, 4 cases showed decreased density of enhanced nodules around the tumor and 6 cases showed partially fused and filled to the center of tumor with no enhancement in the necrotic part. (2) Treatment and pathological examination: all 10 patients underwent completed tumor resection successfully, and no metastasis was found in liver or the hilar region. Results of postoperative pathological examination showed that each of the 10 patients had only one single visible tumor with tumor diameter of 8.0 cm(range, 4.5‒13.5 cm). Of the 10 patients, 7 cases had tumor with complete or incomplete pseudocapsule with clear boundary and 3 cases had tumor without pseudocapsule and the boundary was unclear. All 10 patients had tumor with hard parenchyma and the section was mostly gray and fish like. Among them, patchy or punctate necrosis was seen in 7 cases, small patchy or punctate hemorrhage was seen in 3 cases, and small patchy calcification was seen in 2 cases. Microscopically, the tumor tissue was crisscross, the tumor cells were in spindle shaped, the nuclei were in round, oval, blunt at both ends or in thin rod like, with obvious heteromorphism, large and deeply staining, and obviously division. Immunohistochemical staining showed positive staining of smooth muscle actin, desmin and vimentin. (3) Follow-up and survival: all 10 patients were followed up postoperatively for 6 to 130 months, with a median follow-up time of 55 months. The overall survival time of 10 patients were 10 to 120 months, with a median overall survival time of 46 months. Of the 10 patients, 2 cases died of tumor recurrence and distant metastasis 10 and 11 months after operation, respectively and 8 cases survived >12 months.

Conclusions Results of plain CT scan of PHLMS show clear or unclear cysts and solid masses with uneven density. Results of enhancement CT scan of PHLMS show persistent uneven enhancement in tumor parenchyma and the surrounding area.