Infantile Fibrosarcoma of the Hand: Limb-Sparing Treatment With Modern Targeted Oral Chemotherapy and Conservative Surgical Resection.

Infantile fibrosarcoma is a locally aggressive tumor that traditionally requires chemotherapy and radical excision or amputation. Recently, neoadjuvant therapies that exploit its NTRK fusion oncogenes have been used to decrease the extent of surgical resection. However, the management of morphologically similar infantile fibrosarcoma-like tumors has not been well characterized. We report a case of an anaplastic lymphoma kinase-driven infantile fibrosarcoma-like neoplasm of the hand that was managed using a multimodal, limb-sparing approach. A 35-week gestation neonate presented with a vascular mass on the volar aspect of his left hand. Neoadjuvant treatment with the anaplastic lymphoma kinase inhibitor lorlatinib led to considerable tumor regression, which enabled conservative surgical resection and preservation of the hand. At 2 years of follow-up, the patient remains on lorlatinib therapy without recurrence and demonstrates excellent hand function despite moderate scar contractures. This case highlights the efficacy of neoadjuvant therapy combined with resection in managing infantile fibrosarcoma-like tumors.