School of Podiatric Medicine Publications and Presentations
Document Type
Poster
Publication Date
9-2025
Abstract
Introduction: Solitary spindle cell nodules on the foot in pediatric patients are rare and diagnostically challenging. Dermatofibroma (benign fibrous histiocytoma), a common adult dermal lesion, is infrequently observed in children under 18.
The spectrum of pediatric spindle cell tumors includes reactive entities like nodular fasciitis and dermatomyofibroma, benign neoplasms such as myofibroma, and malignant tumors including spindle cell rhabdomyosarcoma, fibrosarcoma, and dermatofibrosarcoma protuberans (DFSP). Accurate differential diagnosis is essential, as DFSP requires wide excision or Mohs surgery to reduce recurrence risk.
Methods (Case Presentation): An 11-year-old boy presented with a one-year history of a non-healing lesion on the heel, initially treated as a wart without improvement. The lesion was ulcerated, encapsulated, and not painful, but caused irritation with activity. MRI showed a superficial soft tissue mass confined to the skin, with no subcutaneous extension. Due to its atypical, chronic appearance, an excisional biopsy was performed.
Histopathology revealed mitotic figures with spindled fibroblasts in storiform arrangement with histiocytes. Some lesional cells stained positive with CD10, CD68, variably positive CD34, CD43, uniformly but weakly positive actin and Factor XIIIA, but negative for S100, SOX10, cytokeratin, p63, ALK1, CD1a, CD20, CD21, CD30, CD31, CD35, desmin, HMB45, and MelanA. There was no significant pleomorphism, atypia, or increased cellularity. Immunohistochemistry showed features suggestive of several entities. The final diagnosis was benign fibrohistiocytic lesion consistent with dermatofibroma (DF), one type of spindle cell lesion. The patient had an uncomplicated recovery and remains recurrence-free three months post-op.
Results: This case underscores the importance of maintaining suspicion for soft tissue neoplasms in chronic, non-healing pediatric lesions—even when they resemble benign conditions like warts or more common differentials such as retained foreign bodies. Early imaging and biopsy were essential for diagnosis. Accurate interpretation of histology and immunostaining, along with multidisciplinary input from pathology and oncology, ensured appropriate management and patient education.
Discussion: In pediatric patients, persistent spindle cell lesions on the foot necessitate a rigorous diagnostic approach. This case of pediatric dermatofibroma illustrates the need to differentiate benign fibrohistiocytic lesions from malignant mimics such as DFSP, using histologic features, immunohistochemistry, and molecular testing to guide patient management appropriately.
Recommended Citation
Higham, Michael; Campbell, Stephanie; Jean, Naomie; and Killeen, Amanda, "Actin Up and Factor’d In: A Pediatric Spindle Cell Lesion Case Presentation" (2025). School of Podiatric Medicine Publications and Presentations. 114.
https://scholarworks.utrgv.edu/sopm_pub/114
ORCID
0000-0002-4425-4921, 0000-0002-8461-9139
Academic Level
faculty
