Fibrous hamartoma of infancy: radiologic features and literature review

Abstract

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.

Fibrous hamartoma of infancy (FHI) of the parotid region in a 3-year-old female presenting as a huge parapharyngeal tumor: A very rare case presentation

“…These are usually firm in consistency, and may be affixed to the underlying tissue, thus causing a concern for malignancy [5]. Radiological investigations usually are nonspecific, and reveal well delineated soft tissue mass with varying intensities suggestive of fat and muscle tissues [3]. Imaging studies are useful for surgical planning to look for its attachment to surrounding structures.…”

“…Only about 200 cases have been reported so far, emphasizing its rarity and diagnostic ambiguity. These lesions occur commonly in the superficial soft tissues of axilla, upper arm, trunk, or external genital area [3]. Fibrous tumor of infancy very rarely occurs in the parotid region and primary FHI of the parotid region has not been reported in such young age group making this case a unique one Int J Case Rep Images 2020;11:101167Z01RR2020.…”

Imaging of Pediatric Soft Tissue Tumors and Tumor-like Conditions

“…Calcification is rare but was reported in two cases when the FHIs were left until adulthood and thought to represent long-term degenerative change. 47 They may show rapid growth. On US, these lesions are of heterogeneous hyperechogenicity with a "serpentine" pattern and ill-defined or lobulated margin with no significant internal Doppler signal.…”

“…But those lesions lasting until adulthood were reported to have dilated blood vessels. 45,47 On MRI, adipose tissue is high on T1 and T2 and low on STIR, fibrous tissue is low on all sequences, and mesenchymal tissue is embedded within a myxoid stroma and shows a high signal on STIR. The lesions have variable enhancement.…”

“…Whirling appearance was also described in these lesions. [45][46][47] The presence of fat limits the differential diagnosis and includes lipoma, lipoblastoma, lipomatosis, and hemangioma.…”