A 13-year-old girl presented with complaints of rapid enlargement of her left thigh. There was no history of pain/fever/intervention. No EEG was performed as the patient had no symptoms of neural involvement. Examination revealed diffuse enlargement of the thigh. The swelling was non-tender, firm in consistency and had the texture of normal skin.
The patient was further investigated and MRI was advised, which revealed a large ill-defined heterogeneous lesion involving the anterior, medial and some portion of the lateral aspect of the left thigh. The lesion was located predominantly in the subcutaneous region of the thigh with mild extension deep into the intermuscular fascia. The lesion appeared iso-hypointense on T1W and hyperintense on T2Wand STIR images. Interspersed areas of fat were noted within the lesion. No evidence of blooming was noted within the lesion.
On post-contrast scan, the lesion showed minimal heterogeneous enhancement. The vessels were encased by the lesion with no narrowing while the femoral nerve was not seen separately from the lesion. No evidence of any dilated torturous flow void was noted.
The lesion was excised and sent for histopathological examination and the imaging findings were then confirmed.
The patient is in now regular follow-up with no features suggesting recurrence.
The term “Fibrolipomatous hamartoma” was first coined by Mason in 1953 [1]. Fibrolipomatous hamartoma is relatively less common condition.
In cases of fibrolipomatous hamartoma, the perineural and epineural compartments of the involved nerve are infiltrated by mature adipose tissue along with fibrous tissue, which dissect between them and separate individual nerve bundles [2, 3]. The exact aetiopathogenesis of fibro-lipomatous hamartoma has not been well understood. It has been postulated to be congenital in nature, as well as acquired after trauma, nerve irritation, and inflammation [4]. They have a history of slowly growing soft-tissue mass, followed by numbness, pain and decreased sensory or motor function. Examples includes carpal tunnel syndrome [5, 6] The upper extremity is more commonly involved than other sites. There is a marked predilection for involvement of the median nerve, but the ulnar nerve [7] radial nerve [8] and brachial plexus are other reported sites. In about 4 to 22% of the instances, the condition occurs in the lower extremity; case reports and series have described sciatic [9] superficial peroneal plantar [10] and tibial nerve involvement.
On axial images, magnetic resonance imaging reveals T1-hyperintense and T2-hyperintense tissue infiltrating between the hypointense dots and has a co-axial cable-like appearance; on coronal images the serpentine linear hypointense structures show a surrounding spaghetti-like appearance [11, 12]. The fat signal intensity and characteristic cable-like or spaghetti-like appearance of fibrolipomatous hamartoma are pathognomonic of this entity. Fibrolipomatous hamartoma differs from its diagnostic mimics, for example, a well-encapsulated intraneural lipoma arises from the perineurium and presents as a focal fatty mass separated from and eccentric to the nerve fascicles [13, 14].
No current guidelines for the treatment of lipofibromatous hamartoma (LFH) are available. The surgeon and the patient must weigh the potential risks and benefits of surgery against those of conservative management. Overall, treatment is based on the symptoms of the condition, considered on a case-by-case basis. Although some patients with LFH experience no neurologic or functional complications, others do. Medical management has no role, and surgery is reserved for those with neurologic deficits.
The outcomes and prognosis of surgical therapy for lipofibromatous hamartoma (LFH) have ranged from loss of sensory and motor function to full return of both motor and sensory function. Numerous factors affect prognosis, including the degree of involvement, the size of tumour burden, the age of the patient, and surgical technique.
Fibrolipomatous hamartoma
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MRI of the patient’s left thigh shows:
Based on the patient’s age (13 years old), painless swelling in the left thigh, and MRI showing fibroadipose proliferation, the following diagnoses can be considered:
Considering the patient’s age, the location of the lesion, the typical intertwined fat and fibrous strands on MRI, and the lack of significant pain or functional impairment, the most likely diagnosis is fibrolipomatous hamartoma.
Taking into account the patient’s medical history and radiological features, the most probable diagnosis is:
Left Thigh Fibrolipomatous Hamartoma (Neural Fibrolipoma).
For a definitive confirmation, clinical neurological evaluations and pathological biopsy (if feasible) can be considered.
1. Treatment Approach
2. Rehabilitation and Exercise Prescription
In cases with no clear indication for surgery or during the postoperative recovery phase, a gradual functional exercise program is recommended:
During exercise, follow the FITT-VP principles (Frequency, Intensity, Time, Type, Volume, Progression) and ensure patient-specific, safe, and moderate movement to minimize secondary injury due to overload or impact.
Disclaimer: This report is a reference analysis based on available information and cannot replace an in-person consultation or professional medical advice. If you experience discomfort or changes in condition, please seek specialist advice promptly.
Fibrolipomatous hamartoma
