Review
A total of 128 Japanese cases, including the case described above, were reported during the period examined. Eighty-five cases were positive for CD34 and negative for S-100 protein and MDM2 and, thus, were regarded as definitive SCL [4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62] (Supplementary Table 1 ).
The average age of patients at the first hospital visit was 59.2 ± 12.2 years (Table 1 ). The male-to-female ratio was approximately 4:1 (69 males and 16 females). The tumor appeared in the neck in 26 cases (30.6%), the oral cavity in 13 (15.3%), the lower extremities in 12 (14.1%), the shoulder in 9 (10.6%), the back in 7 (8.2%), the head in 7 (8.2%), the chest in 3 (3.5%), the groin and genital area in 3 (3.5%), the abdomen in 2 (2.4%), and the upper extremities in 2 (2.4%), except for 1 case had multiple occurrences across many regions. Among 71 cases with relevant data, the tumor occurred in subcutaneous tissue in 64 cases (90.1%), muscle tissue in 6 (7.1%), and submuscular tissue in 1 (1.2%). Among 66 cases with relevant data, the imaging examination showed a well-demarcated margin in 63 cases (95.5%) and an irregular margin in 3 (4.5%). Among 65 cases with relevant data, the imaging examination showed heterogeneity in 50 cases (76.9%) and homogeneity in 15 (23.1%). Among 33 cases with relevant data, the imaging examination also showed the presence of enhancement in 30 cases (90.9%) and its absence in 3 (9.1%). Among 41 cases with relevant data, the capsule of dissected tumors was present in 38 (92.7%) and absent in 3 (7.3%). Among 80 cases with relevant data, tumors were dissected with a narrow margin in 69 cases (86.3%) and a wide margin in 11 (13.8%). The average follow-up period was 1.3 ± 1.4 years in 65 cases with relevant data on the follow-up period. Recurrence was detected in one (1.5%) of the 65 cases followed up.
We performed statistical analyses of the data described above. Age at the first hospital visit was significantly older in male patients than in female patients; 60.7 ± 11.8 years in male patients vs. 52.6 ± 12.8 years in female patients (p =0.029, the Mann-Whitney U test,Table 2 ). A significant difference was observed in tumor occurrence sites between male and female patients; the tumor occurred in the lower extremities in 7 female patients (43.8%) and the neck in 25 male patients (36.8%) (p =0.014, Pearson’s chi-square test;Table 2 ). A positive correlation was noted between the maximum gross tumor diameter and the period from perception of the tumor to the first hospital visit (p =0.004, a linear regression analysis) (Figure 3 ). Furthermore, a correlation was observed between the maximum gross tumor diameter and contrast enhancement in imaging studies (p =0.05, the Mann-Whitney U test). However, the period from perception of the tumor to the first hospital visit did not correlate with tumor heterogeneity on imaging.