Neuropathology and Applied Neurobiology (2015), 41, 849–852
Expanding the spectrum of livedoid vasculopathy: peculiar neuromuscular manifestations Livedoid vasculopathy (LV) is a rare and recurrent chronic disorder mainly restricted to the skin. LV is characterized by recurrent purpura, livedo reticularis of the legs associated with painful ulcerations, resulting in atrophic, porcelain scars . This disease is considered a thrombo-occlusive vasculopathy of superficial dermal micro-vessels due to either idiopathic cause or secondary to a defined state of thrombophilia . Diagnosis is based on the characteristic skin lesions and presence of intraluminal thrombosis, endothelial cell hyperplasia and sub-intimal hyaline degeneration in dermal vessels . LV is not a vasculitis sensu-stricto, as generally no inflammation occurs within the wall of the vessels, but perivascular inflammation may be present secondarily . Neurological involvement in LV is rare and may expand its nosological spectrum. Symptoms comprise mononeuritis multiplex, and the underlying pathophysiology has been postulated to be the result of ischaemia [5,6]. However, vasculitis has been observed, in an association between LV and periarteritis nodosa (PAN) . From a physiopathological point of view, this entity is surprising, as a general state of hypercoagulability leads to damage confined to the skin and much less frequently to the peripheral nervous system, but not to other tissues. Here, we describe LV patients with a peripheral neuropathy attributed to thrombotic vasculopathy without signs of vasculitis. Furthermore, we illustrate the involvement of the skeletal muscle, characterized by an extreme loss of capillaries, associated with peculiar perifascicular pathology. In a retrospective observational study, primary LV patients (n = 18, 10 females and mean age of 50.1 years) diagnosed by international criteria  were enrolled. We identified three patients, who had undergone combined nerve–muscle biopsy to explore peripheral neurological symptoms. Patients were 58, 44 and 22 years at time of the first skin manifestation (patient A, B and C, respectively). Neu© 2015 British Neuropathological Society
rological signs appeared respectively 10 (patients A), 20 (patient B) and 23 years after (patient C) the first skin manifestation. One patient (patient A) suffered from mononeuritis multiplex. Electroneurography confirmed popliteal sciatic nerve damage and showed injuries of median and ulnar nerves. Patient B suffered from sensory polyneuropathy of lower limbs. Patient C had bilateral dysesthaesia and hypaesthesia of the back of the right foot, and his EMG showed a motor and sensory axonal neuropathy. No proximal weakness was observed in any of the three patients, and all of them had normal CK levels. Other causes of peripheral neuropathy were excluded by extensive laboratory tests, and there was no history of drugs, neurotoxin exposure or association with cancer. All patients showed remarkably similar morphological alterations. A severe loss of myelinated axons, with only few thinly myelinated axons (with minimal signs of axonal regeneration) and endoneurial replacement by fibrous tissue, was the most prominent finding (Figure 1A,B). Furthermore, a relevant formation of collagen pockets on ultra-structural examination illustrated loss of un-myelinated axons (Figure 1C). All fascicles were equally affected. The second observation consisted of enlarged vessels with conspicuous engorgement mainly in the epineurium (Figure 1D). Importantly, in all cases, inflammatory infiltrates basically consisting of CD3+ lymphocytes were detected around enlarged vessels in the epineurium (Figure 1D), however without signs of vasculitis. In addition, we found a remarkable vascular pathology mainly involving capillaries of the endoneurium. Alterations consisted of enlarged endothelial cells, which appeared thickened, occasional basal membrane duplication, apposition of endothelial cells layers, as well as necrosis of capillaries (Figure 1A,E,F). Indirect signs of neuropathy were also observed in all muscle biopsies with neurogenic features consisting of nuclear clumps, grouped atrophic fibres and fibre-type grouping (Figure 1G). Additional myopathic changes included split fibres, and round and hypertrophic fibres with internalized nuclei (Figure 1H). Although neurogenic changes are frequently associated with myopathic features especially during a chronic course of disease, we also detected myopathic changes not attributable to neu849
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Figure 1. (A) Semithin section shows widespread loss of myelinated axons with only a small cluster of axon regeneration, left (methylene blue, original magnification × 400). (B) Staining by Gomori trichrome, illustrates the severe loss of myelin and endoneurial fibrous tissue (Gomori trichrome, original magnification × 200). (C) Ultrastructural analysis reveals loss of unmyelinated axons as well as collagen pockets (EM, original magnification × 30 000). (D) Engorged epineurial vessels are surrounded by perivascular lymphocytic infiltrate (haematoxylin-eosin and inset, Gomori trichrome, both original magnification × 200). (E) Electron microscopy of an endoneurial vessel shows necrosis of the vessel wall (EM, original magnification × 7000) and (F) endothelial cell alterations in another vessel (EM, original magnification × 4000). (G) Grouped fibres are illustrated by NADH-TR (original magnification × 100). (H) The skeletal muscle shows important variation of fibre size, atrophic fibres, internalized nuclei and split fibres (Gomori trichrome, original magnification × 400). (I) Vacuolar changes are found in the penultimate layer of the fascicle (Gomori trichrome, original magnification × 200). (K) The vacuoles do not contain Periodic acid Schiff (PAS)-positive material (PAS, original magnification × 200). (L) The upper part of the photomicrograph shows severe loss of capillaries, whereas the adjacent fascicle in the lower part shows much denser vascularization (CD31, original magnification × 100). (M) In comparison, skeletal muscle of a neurogenic process shows a normal density of CD31+ capillaries, while (N) in DM, a loss of capillaries can be detected (CD31, original magnification × 400). (O) Macrophages are numerous in the endomysium, frequently surrounding clusters of vessels (CD68, original magnification × 400). (P) Significant numbers of CD3+ T cells can also be stained in the endomysium (CD3, original magnification × 200), while (Q) sarcolemmal MHC class I staining highlights only occasional muscle fibres (MHC class I, original magnification × 200). All patients gave informed consent to participate in the study, and approval was obtained from the French institutional review board.
ropathy. Numerous non-rimmed vacuoles, also lacking sarcolemmal features, were present within the fibres, with a very peculiar distribution. Vacuoles occurred only in the perifascicular fibres but, importantly, sparing the most peripheral layer of fibres (Figure 1I). Periodic acid Schiff staining showed that vacuoles did not contain glycogen (Figure 1K), and they were LC3, p62 and acetylcholine esterase negative (data not shown). Abnormalities in COX or SDH stains were absent (data not shown). Furthermore, an extreme but variable loss of capillaries was present. Some fascicles showed nearly total loss of vessels with clustering of small capillaries in the perimysium (Figure 1L). In comparison, skeletal muscle of a neurogenic process shows a normal density of capillaries (Figure 1M), while in DM, a loss of capillaries can be detected (Figure 1N). The majority of endomysial capillaries appeared enlarged, sometimes with a diameter in the same range as the adjacent myofibre (Figure 1L). Some capillaries also harboured a thickened wall (Figure 1L). Nevertheless, we never observed significant perifascicular atrophy, focal necrosis or micro-infarcts. No endocapillary or sarcolemmal C5b-9 deposits were noted (data not shown). Also, tubuloreticular endothelial inclusions were never observed. Inflammatory infiltrates were present and only located around the clustered capillaries. Infiltrates were mainly composed of CD68+ macrophages (Figure 1O), but also some CD3+ T cells were present (Figure 1P). Sarcolemmal MHC-I staining was weak on a few myofibres and did not highlight the perifascicular region (Figure 1Q). The patients received several treatments considered specifically directed against the vasculopathy (anti© 2015 British Neuropathological Society
coagulants, immunosupressors, e.g. corticosteroids +/− endoxan, etc.) without any positive effect on the course of their neuropathy. Presence or absence of vasculitis as the origin of neurological signs is of great importance in LV because of therapeutic implications. In this regard, analysis of nerve and muscle tissues is crucial also to exclude other diagnoses and concomitant pathologies. In our series, we did not observe signs of vasculitis as others described . As PAN and LV with peripheral neuropathy may have the same clinical presentation, a very careful assessment of the nature of vascular inflammation is necessary to avoid any confusion. As our patients had a rather long time lapse between skin and nerve manifestations, it may be difficult to prove a link between these two events. However, we and others have clearly demonstrated the same alterations of the vasculature in both tissues, strongly suggesting a common mechanism leading to ischaemic damage. We also documented a very striking and uncommon vasculopathy of the skeletal muscle including severe loss of capillaries, associated with endomysial grouping of thickened and/or enlarged capillaries. Of note, these two latter features are probably of compensatory nature and/or the consequence of hypoxia. DM is an auto-immune myopathy characterized by both perivascular inflammation and a vasculopathy, associated with perifascicular fibre atrophy at advanced stages. To date, it is unknown if vasculopathy is the primary event in DM. LV may serve as a natural model of inflammatory vasculopathy to study its consequence on skeletal muscle. However, we show that the morphological pattern of both muscle fibre injury (sparing of the outer layer of the fasNAN 2015; 41: 849–852
cicle and lack of conspicuous atrophy) and vasculopathy is different in DM and LV (grouped capillaries and thickened capillary walls). This indicates that the mere occlusion of capillaries in LV does not lead to a DM-like picture. Along that line, Gitiaux et al.  suggest that involvement of skeletal muscle vasculature in DM occurs upstream of capillaries in large arcade arteries. To conclude, we showed that vasculopathy in LV might occur in the peripheral nervous system and is associated with a severe loss of myelinated axons, but we failed to observe any signs of vasculitis. We report a specific myopathy in patients with LV, characterized by a very severe and unique type of vasculopathy and perifascicular pathology.
Acknowledgements We thank Petra Matylewsky and Hanna Plückhan for expert technical assistance.
Author contributions YA, MT, WS and OB drafted and revised the manuscript, designed the study concept, did the analysis of data, and participated in their acquisition. TM, H-HG, SB and CF analysed the data and/or participated in their acquisition and revised the manuscript. Y. Allenbach*,†,‡ M. Tourte†,‡ W. Stenzel* H.-H. Goebel* T. Maisonobe§ C. Frances¶ S. Barete¶,** O. Benveniste†,‡ *Department of Neuropathology, Charité – Universitätsmedizin, Berlin, Germany, †Department of Internal Medicine and Clinical Immunology, Hospital University Department: Inflammation, Immunopathology and Biotherapy (DHU i2B), Assistance Publique – Hôpitaux de Paris, Pitié-Salpêtrière University Hospital, ‡Inflammatory Muscle Team, Inserm U974, Sorbonne Université, ¶Assistance Publique – Hôpitaux de Paris, Tenon University Hospital, Department of Dermatology, Sorbonne University, **Assistance Publique – Hôpitaux de Paris, Pitié-Salpêtrière University Hospital, Dermatology unit, Sorbonne University, University Pierre et Marie-Curie-Paris 6, and §Assistance Publique-Hôpitaux de Paris, Department of Neuropathology, Pitié-Salpêtrière University Hospital, Paris, France
© 2015 British Neuropathological Society
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Received 5 January 2015 Accepted after revision 28 March 2015 Published online Article Accepted on 14 April 2015
NAN 2015; 41: 849–852