Asymptomatic cerebellar lesions in linear scleroderma “en coup de sabre”

Clinical History

A 6-year-old boy presented with a pruritic linear left parieto-occipital scalp lesion, characterized by local skin atrophy and alopecia. Biopsy revealed dermal fibroplasia with perivascular and perifollicular inflammation. The patient was neurologically normal with no abnormal cerebellar signs throughout his entire course, including a 2-year follow-up.

Imaging Findings

Initial brain MR (Figure 1a) at time of diagnosis revealed a minimally prominent left diploic vein with communication with the posterior sagittal sinus. A CT venogram of the head (Figure 1b) identified thinning of the skull at the site in question without any obvious sinus percranii. No parenchymal lesions were seen on initial head CT and MR images.

A scheduled MR (Figure 2) two years after diagnosis identified a nonspecific ill-defined T2-hyperintense lesion involving the left cerebellar hemisphere. There was no mass effect or restricted diffusion associated with the signal abnormality. Ill-defined punctate areas of contrast enhancement and few punctate foci of susceptibility effect were seen within the lesion, presumably microhaemorrhages or foci of calcification. Apart from post-biopsy changes, the scalp and soft tissue thinning previously identified had remained stable; the rest of the MR was unremarkable. All abnormalities were ipsilateral to the left parieto-occipital cutaneous scar.

Discussion

Linear scleroderma en coup de sabre (LScs) is a local scleroderma confined to forehead and scalp, affecting two in 100, 000 with peak incidence at thirteen years [1-2]. Named for the semblance to a scar from a sabre blow, the cutaneous lesion of LScs is typically depressed, ivory-colored, and surrounded by violaceous borders. It may be accompanied by soft tissue lesions, brain parenchymal changes, and neurological symptoms [3-7]. The commonest are focal seizures, followed by headache, hemiparesis, cranial nerve deficits, and peripheral neuropathy [1-3]. Severity of these symptoms, however, does not correlate with the extent of a visible brain lesion. If they arise at all, imaging abnormalities can appear months before or after the scar [4-5]. Nonspecific T2 hyperintensities are commonest, then calcifications, cerebral atrophy, outer diploe and scalp thinning, subcortical calcifications, grey-white interface blurring, and microhaemorrhages [3-4]. They are classically found within the fronto-parietal lobes, ipsilateral to the cutaneous scar [2]. Diagnosis of LScs is clinical but confirmed by biopsy of the cutaneous lesion.

The pathogenesis of LScs is unclear. Skin trauma can develop into the scleroderma, suggesting excessive collagen deposition. Perivascular lymphocytic infiltrate and intravascular calcification seen in biopsies support a neurovasculitis process, while elevated levels of autoantibodies lend credibility to autoimmune pathology [1-7].

Asymptomatic paediatric LScs cases with positive neuroimaging abnormalities are rare. A multinational study found only five of 750 cases positive for brain lesions but benign clinically [1]. Only one other paediatric case of LCsc has involved the cerebellum, but presented with vertigo [8]. Nevertheless, we conclude our patient had LScs as his brain lesions were stable and located classically ipsilateral to the cutaneous scleroderma (confirmed by skin biopsy). An asymptomatic adult case described by Choi et al. has suggested how such benign presentations are possible. Punctate enhancements on susceptibility-weighted T1 MR suggested microbleeds around vascular walls and increased permeability. A subsequent transient interstitial oedema would explain the imaging findings but benign clinical presentation [7].

In summary, some paediatric LScs patients present with neurological symptoms, with a subset bearing detectable intracranial abnormalities. Only a small fraction of LScs cases, however, shows intracranial findings without symptoms. The unpredictable clinical nature and neurological involvement of LScs serve as causes for neuroimaging screening and routine follow-up for reassessment and therapy guidance [3]. LScs confined to the cutaneous lesion can be managed by phototherapy, but when deep tissues become involved, methotrexate and prednisone become the first line treatments [9-10].

Differential Diagnosis List

Final Diagnosis

Linear scleroderma “en coup de sabre” of the cerebellum

URL:	https://www.eurorad.org/case/12662
DOI:	10.1594/EURORAD/CASE.12662
ISSN:	1563-4086