Excisional biopsy of suspected benign soft tissue tumors of the upper extremity: correlation between preoperative diagnosis and actual pathology.

BACKGROUND: Tumors of the upper extremity are common and mostly benign. However, the prevalence of discordant diagnosis of a solid hand tumor is less studied. The objectives of this retrospective study were (1) to determine the proportion of patients with a different (discrepant or discordant) pathological diagnosis compared to the preoperative diagnosis, (2) to determine the prevalence of the types of pathologies encountered at excisional biopsy for suspected benign tumors, and (3) to determine the types of tumors diagnosed when the surgeon does not make a preoperative diagnosis.

METHODS: One hundred and eighty-two suspected benign soft tissue tumors of the upper extremity with a preoperative diagnosis other than ganglion cyst were excised by one of three surgeons over a 10-year period. A preoperative diagnosis was applied for 125 tumors. No preoperative imaging was used.

RESULTS: Only 26 of the 125 tumors (21 %) with a preoperative diagnosis were discrepant. The tumors that were most likely to have a discrepant diagnosis were vascular tumors (32 %) and other less common benign tumors (33 %). Among the entire cohort of 182 tumors, lipomas (19 %), giant cell tumors of tendon sheath (GCTTS; 19 %), and vascular tumors (16 %) were the most frequent pathological diagnoses. Among the 57 tumors that did not have a preoperative diagnosis, most were vascular tumors (23 %), fibromas (14 %), and GCTTS (11 %). One tumor without a preoperative diagnosis was a malignant tumor, but we consider this unusual and possibly spurious.

CONCLUSIONS: A hand surgeon's preoperative diagnosis without imaging is usually correct prior to excision of a mass in the hand. Discrepant diagnoses are usually benign and do not alter treatment.

LEVEL OF EVIDENCE: Prognostic II.