Marek, Tomáš

BACKGROUND Macrodystrophia lipomatosa (MDL) is characterized by progressive overgrowth affecting soft tissues and bony structures and is part of lipomatous overgrowth syndromes. MDL has been associated with lipomatosis of the nerve (LN), an adipose lesion of nerve that has a pathognomonic magnetic resonance imaging (MRI) appearance as well as a mutation in the PIK3CA gene. The authors present a case of occult LN in the setting of MDL. OBSERVATIONS A 2-year-old boy with progressive soft tissue overgrowth of his proximal right lower extremity was initially diagnosed with neurofibromatosis type 1 (NF1). At our institution, NF1 as well as other overgrowth syndromes including PTEN hamartoma tumor syndrome were excluded. He was diagnosed as having so-called MDL. Upon reinterpretation of the patient’s MRI studies, short-segment LN involving the proximal sciatic nerve and part of lumbosacral plexus was identified. He underwent 2 debulking/liposuction procedures for soft tissue overgrowth. Genetic testing of tissue revealed a mutation in PIK3CA . LESSONS Thorough clinical examination (for signs of overgrowth) as well as an MRI study of the entire neural pathway is a critical part of the diagnostic workup to evaluate for LN. The authors believe that an increasing association of LN, even when occult, will emerge that will explain many cases with marked nerve-territory overgrowth.

OBJECTIVE Perineural spread of breast cancer to the brachial plexus can lead to pain, sensory alterations, and upper-extremity weakness. Although rare, perineural spread is an often-misdiagnosed long-term complication following breast cancer diagnosis. The objective of this study was to critically review the clinical, radiological, and pathological findings of biopsy-proven perineural spread of breast cancer to the brachial plexus. METHODS This is a retrospective study from a single institution in which a total of 19 patients with brachial plexus involvement from perineural spread of breast cancer who underwent fascicular biopsy between 1999 and 2021 were identified. Clinical, radiographic, and pathological data were retrospectively collected. Descriptive statistics were calculated for the cohort. RESULTS The mean age of patients at the time of diagnosis of breast cancer perineural spread was 60.6 ± 11.5 years. The diagnosis of brachial plexopathy due to perineural spread was on average 12 years after the primary diagnosis of breast cancer. There was also a delay in diagnosis due to the rarity of this disease, with a mean time from initial symptom onset to diagnosis of perineural spread of 25 ± 30 months. All patients at the time of presentation had upper-extremity weakness and pain. Nearly all patients demonstrated T2 signal change and nodular so-called sugar-coating contrast enhancement on brachial plexus MRI. Similarly, all patients who underwent PET/MRI or PET/CT had increased FDG uptake in the involved brachial plexus. Breast cancer perineural spread has an overall poor prognosis, with 16 of 19 patients dying within 5.9 ± 3.0 years after diagnosis of perineural spread. CONCLUSIONS Perineural spread should be considered in patients with a history of breast cancer, even 10 years after primary diagnosis, especially in patients who present with arm pain, weakness, and/or sensory changes. Further diagnostic workup with electrodiagnostic studies; brachial plexus MRI, PET/CT, or PET/MRI; and possibly nerve biopsy is warranted to ensure accurate diagnosis.

AbstractBackgroundLipomatosis of nerve (LN) is a complex peripheral nerve disorder characterized by fibrofatty nerve enlargement. MRI of this pathology is pathognomonic and obviates a diagnostic biopsy. Mutation in PIK3CA has been associated with LN cases with nerve‐territory overgrowth which may occur in some cases. We evaluate an association of LN of the sciatic nerve and early‐onset colonic diverticular disease and discuss the potential pathogenesis.MethodsOur institutional database was searched for LN cases. Available information of identified cases was reviewed, and cases with a confirmed diagnosis of LN affecting the lumbosacral plexus and/or sciatic nerve; available MRI of the affected nerve(s); and diverticular disease occurring in the area supplied by the nerve(s) affected by LN were further analyzed. PIK3CA mutation testing was performed on available tissue samples.ResultsWe identified 10 LN cases of lumbosacral plexus and/or sciatic nerve. Of these, three fulfilled our inclusion criteria. All three patients had concomitant colonic diverticular disease, diagnosed at a relatively young age. MRI studies of these cases showed LN involvement of the sacral nerves innervating the sigmoid colon. All three also had abnormal diagnostic workup including various GI tests and evidence of associated nerve‐territory overgrowth. Colonic tissue samples for PIK3CA mutation were negative.ConclusionWhile the pathogenesis of the colonic diverticular disease is increasingly recognized as being multifactorial, our observations are consistent with the potential role of autonomic nervous system dysfunction affecting either the pelvic floor musculature, or the colon itself (or both) in a subset of patients with early‐onset diverticular disease.

OBJECTIVELipomatosis of nerve (LN) is a massive enlargement of a nerve due to abundant proliferation of adipose and fibrotic tissue within the epineurium—part of the spectrum of adipose lesions of nerves, including intra- and extraneural lipomas. LN has been frequently associated with soft-tissue and/or osseous overgrowth. Unfortunately, much confusion exists since many names have been used for LN (e.g., fibrolipomatous hamartoma, macrodystrophia lipomatosa, and so on). To better understand this condition and to evaluate its association with nerve-territory overgrowth, the authors attempted to compile the world’s literature on published LN cases.METHODSPubMed and Google Scholar databases were searched to identify published articles on LN cases, using a variety of terms. Publications in all languages were assessed. All publications with cases determined likely to be LN were read. Cases that provided clear clinicopathological and/or radiological evidence of LN were labeled as “definite” and cases that demonstrated features of LN (e.g., nerve-territory overgrowth) but lacked definite proof of nerve involvement were labeled as “probable.”RESULTSInitial screening revealed a total of 2465 papers. After exclusions, 281 publications reported cases with a definite diagnosis of LN and 120 articles reported cases with a probable diagnosis of LN. The authors identified 618 definite and 407 probable cases of LN. Sex distribution was balanced (51% female). Early diagnosis was common, with two-thirds of patients having symptoms in the 1st decade of life. The most commonly affected nerve was the median nerve (n = 391). Nerve-territory overgrowth was common (62% definite LN; 78% combined cases); overgrowth was exclusive to the territory of the affected nerve in all cases but 5.CONCLUSIONSThe authors present a comprehensive review and analysis of the literature of LN cases. One of the main findings was the nerve-territory overgrowth was associated with LN, especially when present earlier in life. The authors believe that all cases of LN associated with overgrowth can be explained on anatomical grounds, even in the few reported cases in which this is not immediately obvious.