Small indeterminate superficial soft tissue masses: relationship between depth and histological grade

To determine whether the location of a small, indeterminate soft tissue mass within the subcutaneous compartment is related to its histological grade.

All Sarcoma Service referrals over a 12 month period of small (<3 cm) superficial soft tissue masses, indeterminate by MRI evaluation which subsequently underwent primary excision biopsy were included. Lesions were categorised by their anatomical location in the subcutaneous compartment. Histopathological diagnoses were categorized according to¹² WHO 2013. χ² statistical analysis was performed to determine the relationship between lesion depth and histological grade.

The study included 43 patients, mean age 42 years (range 15-71 years). Within the subcutaneous compartment, 16 lesions were categorized as superficial, 9 lesions central and 18 lesions deep, of which 9 were non-neoplastic, 29 benign, 1 intermediate-grade and 4 malignant. Location in the deep aspect of the subcutaneous compartment was associated with a higher risk of intermediate or malignant histology (p = 0.02).

The location of a small, indeterminate soft tissue mass within the subcutaneous compartment may be an indicator of histological aggressiveness. Lesions in the deep subcutaneous compartment are more likely to be intermediate-grade/malignant lesions. Therefore, if considering excision biopsy as definitive treatment, a wider margin may be appropriate.

Small, indeterminate soft tissue masses can be aggressive and the anatomical depth within the subcutaneous tissue may be a potential indicator of histological aggressiveness.