Rare case of Intraneural Lipoma of Digital Nerve

Lipomas, although ubiquitous, are extremely uncommon in digital nerves. We present a 68-year-old male patient with right ring finger radial digital nerve intraneural lipoma. The tumor was enucleated preserving all the nerve fascicles. We present this case to highlight the rare occurrence of lipomas within a digital nerve.

Fibrolipomatous Hamartoma (FLH) of Median Nerve: A Rare Case Report and Review

INTRODUCTION

Fibrolipomatous hamartoma (FLH) is a benign tumorous condition of adipose tissue. It is a slow growing, rare tumour involving peripheral nerves with uncertain aetiology. The clinical presentation varies as per presenting severity. The gold standard to diagnose this rare entity is MRI and its management is still controversial. In this report, we have described one such rare presentation of FLH involving Median Nerve in an adolescent male who successfully witnessed resolution of symptoms following our surgical intervention for the same.

CASE PRESENTATION

A 17-year-old male presented to our hospital with a history of swelling in his left hand since past 1 year. The detailed clinical evaluation revealed an irregular fusiform swelling extending from the ulnar aspect of wrist proximally to the thenar eminence along with involvement of the base of 2nd, 3rd and 4th fingers of left hand with consistency varying from soft to firm, tinel's sign positive and a terminal restriction of palmar and dorsiflexion movements. Notably, motor weakness and sensory loss were not elicited. The definitive diagnosis was established by MRI of the left hand. With due consent, the patient was undertaken for surgical intervention whereby his carpal tunnel was decompressed and biopsy of the lesion was sent for further histopathological evaluation as per the protocol. The absolute resolution in symptoms was reported by the patient following our intervention.

CONCLUSION

A meticulous clinical and radiological correlation is required to diagnose such rare clinical entity for improvising the functional quality of life. There is no definitive treatment for lipomatosis of nerve. However, a conservative approach is commonly advocated with successful results from decompression as in our patient.

Intraneural lipomas: institutional and literature review

BACKGROUND

Adipose lesions of nerve can be envisioned as a spectrum ranging from intraneural/extraneural lipomas to lipomatosis of nerve (LN). We have noticed that intraneural lipomas are not as a homogenous group as previously thought and demonstrate differences which have clinical implications. To better understand intraneural lipomas, we conducted a search of cases at our institution and published cases in the world's literature.

MATERIALS AND METHODS

Mayo Clinic's database was searched between years 1994-2018. Published cases were identified using PubMed and Google Scholar databases. Following terms were used: intraneural lipoma, lipoma and nerve, lipoma and neuropathy, lipofibroma and nerve, fibrolipoma and nerve and neural lipoma as well as lipofibroma and fibrolipoma alone. Cases that could be clearly identified as intraneural lipomas by the location of the lipoma within the epineurium were included for analysis. These cases were then sub-classified as encapsulated intraneural lipomas or hybrid intraneural lipomas (demonstrating features of both intraneural/extraneural lipomas and LN) based on their characteristics.

RESULTS

We identified 12 cases at our institution (8 encapsulated, 4 hybrid) and 24 published cases (21 encapsulated, 3 hybrid). The most commonly affected nerve was median both at our institution and in the published cases. Encapsulated cases were found to be relatively easy to resect. Hybrid cases demonstrated variable degree of interdigitating fat between the fascicles and were relatively difficult to resect.

CONCLUSION

Intraneural lipomas exist as two separate entities with distinct clinical implications. Although rare, this should be taken in account when planning surgery. Terminology should be clarified to prevent ambiguity and confusion.