Fibrous hamartoma of infancy: radiologic features and literature review.

Background: Fibrous hamartoma of infancy(FHI) is a rare benign lesion most frequently occurring within the first year of life. So far, just over 200 cases have been reported in the English literature, in which the radiologic findings of FHI have not been fully described. Herein, 2 adult cases of FHI receiving treatment in our hospital and the published cases searched on PubMed are reviewed, with the emphasis on the discussion of the spectrum of MR findings and their histologic correlation.

Case Presentation: We present two adult cases who aged 47 years and 19 years with slow growing masses beginning from their childhood in the posterior craniocervical area. On CT and MR imaging, the tumours showed as the superficially located lesions with ill-defined margins that involved the subcutaneous layer and its underlying muscles. The size of the lesions were 21.3 × 16.7 × 16 cm in case 1 and 20.2 × 19.3 × 13.6 cm in case 2. The tumours demonstrated heterogeneous intensities/signals with the adipose tissue presenting as the disperse strands or small focus of fatty intensity/signal. Parallel or whirling appearance, and dilated vessels were delineated in the cases. Contrast enhancement was administered in case 1 and marked enhancement was found.

Conclusions: The usually observed manifestation of FHI on CT and/or MR imaging is the strands of adipose/fibrous intensities traversing the lesions, with the characteristic parallel or whirling appearance in some cases. The tumours with ill-defined margins have the tendency to involve the underlying muscles. Some fibroblastic and adipocytic tumours should be ruled out in differential diagnosis.