A Morphological Study of Evolution of Cutaneous Polyarteritis Nodosa

Cutaneous vasculitis: insights into pathogenesis and histopathological features

The mechanisms underlying the onset and progression of vasculitis remain poorly understood. This condition is characterized by damage to the vascular wall, recruitment of inflammatory cells, and subsequent structural remodeling, which are hallmarks of vasculitis. The histopathological classification of vasculitis relies on the size of the affected vessel and the predominant type of inflammatory cell involved - neutrophils in acute cases, lymphocytes in chronic conditions, and histiocytes in granulomatous forms. Pathological changes progress in every context, and a single vasculitic pattern can be associated with various systemic conditions. Conversely, a single causative agent may lead to multiple distinct clinical and pathological manifestations of vasculitis. Moreover, many cases of vasculitis have no identifiable cause. A foundational understanding of the normal structure of the cutaneous vascular network is crucial. Similarly, identifying the cellular and molecular participants and their roles in forming the "dermal microvascular unit" is propedeutical.

This review aims to elucidate the complex mechanisms involved in the initiation and progression of vasculitis, offering a comprehensive overview of its histopathological classification, underlying causes, and the significant role of the cutaneous vascular network and cellular dynamics. By integrating the latest insights from studies on NETosis and the implications of lymphocytic infiltration in autoimmune diseases, we seek to bridge gaps in current knowledge and highlight areas for future research. Our discussion extends to the clinical implications of vasculitis, emphasizing the importance of identifying etiological agents and understanding the diverse histopathological manifestations to improve diagnostic accuracy and treatment outcomes.

Case report: Polyarteritis nodosa as a substrate for a massive myocardial infarction

This report describes a rare case of a global myocardial infarction caused by severe vasospasm of the coronary arteries secondary to the administration of pyridostigmine in a patient with polyarteritis nodosa (PAN). Details about the clinical presentation, the typical electrocardiographic pattern of multivessel disease, the differential diagnoses suspected in the multi-imaging approach, and the treatment of cardiogenic shock are described. The definitive diagnosis of infarction and the histopathological findings compatible with polyarteritis nodosa were made by autopsy.

The ratio of CD163-positive macrophages to Iba1-positive macrophages is low in the intima in the early stage of cutaneous arteritis

The etiology of polyarteritis nodosa (PAN) and localized PAN, including cutaneous arteritis (CA), remains unknown; however, initial endothelial damage has been implicated. The intima of the vasculitis lesions is predominantly infiltrated by innate-like bystander-activated CD8 T cells, in addition to the macrophages. Macrophages are among the major inflammatory cells involved in innate immunity and are classified into M1 and M2 subtypes. M1-type macrophages kill pathogens and cause inflammation, while M2-type macrophages promote the repair of tissues. Macrophage subtypes infiltrating in PAN and localized PAN vasculitis lesions have not yet been investigated. Innate immune response to a triggering factor on the endothelial cell surface may initiate CA pathogenesis. Thus, many M1-type macrophages may infiltrate in the intima during early CA. We assessed this hypothesis by immunohistochemical observation of macrophage phenotypes and polarization. Twenty-seven skin biopsy specimens from patients with CA were retrieved. Based on histology, we classified CA into four phases. The phenotypes of infiltrating macrophages in CA were evaluated by immunohistochemistry using antibodies against Iba-1, a pan-macrophage marker, and CD163, an M2-type macrophage marker. Our results showed that the ratio of CD163-positive M2-type macrophages to Iba1-positive macrophages was lower in the intima in the early stage of CA than in the later stage. In the media to adventitia, there was no significant difference in the ratios between these stages. These findings indicate that innate immunity is involved in the intima in the early stage of CA, suggesting that a trigger for CA might exist in endothelial cells.

Eosinophilic granulomatosis with polyangiitis: Cutaneous clinical and histopathologic differential diagnosis

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare, but severe systemic vasculitis that can affect skin and other organ systems. Diagnostic criteria have evolved, and many attempts have been made to classify the vasculitides based on clinical and/or histopathologic features, with an aim to develop standardized criteria. According to the EGPA Consensus Task Force recommendations, EGPA is a syndrome of asthma, eosinophilia, pulmonary infiltrates, and extrapulmonary vasculitis (such as cutaneous involvement with purpura). Histopathologic evidence of vasculitis in EGPA may be associated with eosinophilic infiltration and/or perivascular granulomatous inflammation. We review clinicopathologic criteria of this enigmatic vasculopathy.

Lymphocytic thrombophilic arteritis with lower-limb ulcers

Lymphocytic thrombophilic arteritis is a recently described entity, histopathologically characterized by lymphocytic vasculitis that affects the arterioles of the dermo-hypodermic junction, associated with deposition of fibrin and a luminal fibrin ring. A 49-year-old female patient presented with achromic maculae and a well-defined ulcer on the medial aspect of the left lower limb. The biopsy showed intense inflammatory infiltrate in the papillary dermis with a predominance of lymphocytes, and medium-caliber vessels surrounded by mononuclear infiltrates in the deep reticular dermis. Masson’s trichrome staining showed intense destruction of the muscle layer of the vascular wall and a fibrin ring. Good clinical response was attained with azathioprine. The authors believe that the ulceration might be another clinical presentation or represent an atypical progression of this condition.

Cutaneous lymphocytic thrombophilic (macular) arteritis

Macular arteritis (MA) has a striking discordance between the clinical presentation of hyperpigmented macules and the histopathologic findings of a lymphocytic arteritis with intraluminal hyalinized fibrin ring and thrombosis. It has been proposed that MA represents the chronic, indolent, lymphocytic form of the neutrophil-predominant cutaneous polyarteritis nodosa. MA usually affects middle-aged women asymptomatically on the legs. There is also a slightly more severe variant with more infiltrated plaques and livedo racemosa, termed lymphocytic thrombophilic arteritis. MA and lymphocytic thrombophilic arteritis have similar histologic features, both with a largely intact vascular elastic lamina, despite the abundant fibrin and endarteritis obliterans. There is no evidence for progression from MA to lymphocytic thrombophilic arteritis to cutaneous polyarteritis nodosa, and aggressive therapy should be avoided in MA, given the indolent, benign disease course.

Cutaneous arteriolitis: A novel cutaneous small vessel vasculitis disorder clinicopathologically different from cutaneous polyarteritis nodosa and cutaneous venulitis

Cutaneous vasculitis can be classified into two types based on the affected vessel size: small vessel vasculitis predominantly affecting dermal venules, and muscular vessel vasculitis as found in cutaneous arteritis predominantly affecting arteries located at the dermal-subcutaneous junction. We describe two cases with a novel small vessel vasculitis disorder, which exclusively affected arterioles in the mid-dermis, and show clinical and pathological difference distinct from cutaneous polyarteritis nodosa and cutaneous venulitis. Both patients were male, and presented with painful infiltrative plaques, involving the palms, soles, and thighs without extracutaneous involvement except for fever and arthralgia. Histopathological examination revealed vasculitis in the mid-dermis characterized by a predominant infiltration of neutrophils with vessel wall fibrinoid necrosis and leukocytoclasia identical to the features of leukocytoclastic vasculitis, except that the affected vessels were arterioles rather than venules. Serological examinations showed normal levels of serum complements, immune complexes, and antineutrophil cytoplasmic antibodies, and vasculitis disorders associated with systemic diseases were excluded in both patients. The patients showed a good response to short-term treatment with prednisolone up to 30 mg. This novel cutaneous arteriolitis clinicopathologically different from both cutaneous venulitis and cutaneous arteritis appears to be a skin-limited disorder.

A Case of Cutaneous Arteritis Presenting as Infiltrated Erythema in Eosinophilic Granulomatosis With Polyangiitis: Features of the Unique Morphological Evolution of Arteritis as a Diagnostic Clue

Eosinophilic granulomatosis with polyangiitis (EGPA, formerly Churg-Strauss syndrome) is a rare systemic vasculitis affecting small- and medium-sized vasculature, associated with asthma and eosinophilia. Different levels of vasculitis in cutaneous lesions have been observed, including dermal small vessel vasculitis and subcutaneous muscular vessel vasculitis. Although the EGPA-associated small vessel vasculitis described as leukocytoclastic vasculitis can be often found in the documented literature, the features of subcutaneous muscular vessel vasculitis in EGPA-associated cutaneous lesions have been rarely demonstrated clinically and histopathologically in English literature. Herein, we report a case of EGPA involving infiltrated erythema on the extremities, with different stages of cutaneous arteritis characterized by eosinophilic arteritis and granulomatous arteritis in the same affected artery. We present this as a unique diagnostic clue for EGPA.

Lymphocytic thrombophilic arteritis and cutaneous polyarteritis nodosa: Clinicopathologic comparison with blinded histologic assessment

BACKGROUND

Lymphocytic thrombophilic arteritis (LTA), or macular lymphocytic arteritis, is defined by a primary lymphocytic vasculitis. However, the nosology of LTA has been controversial, with speculation that it may represent an indolent non-nodule-forming variant of cutaneous polyarteritis nodosa (cPAN).

OBJECTIVE

This study compares the clinicopathologic features of patients with LTA or cPAN to assess if these conditions should be considered distinct entities.

METHODS

This is a cross-sectional study of all LTA and cPAN cases at a single tertiary center using prospectively collected clinical data and blinded histologic assessment.

RESULTS

The study included 17 patients with LTA and 13 patients with cPAN. Clinically, cases of LTA were distinguished by a more widespread pattern of livedo racemosa, which was noninfiltrated and asymptomatic. In contrast, cPAN was associated with localized starburst livedo, purpura, and episodic features including nodules, pain, and large inflammatory ulcers. When patients were separated according to the presence (>5%) or paucity (≤5%) of neutrophils on blinded histology review, they had distinct clinical features and differences in disease course.

LIMITATIONS

This was a single-center study.

CONCLUSION

Our data support the classification of LTA and cPAN as separate entities rather than a spectrum of the same disorder and highlight the importance of clinicopathologic correlation in distinguishing these conditions.

Interobserver reliability of histopathological features for distinguishing between cutaneous polyarteritis nodosa and superficial thrombophlebitis

AIMS

Interobserver reliability of histopathological features in differentiation between cutaneous polyarteritis nodosa (cPAN) and superficial thrombophlebitis (ST) by assessment of inter-rater agreement of five histological features was investigated.

METHODS AND RESULTS

All sections of cPAN and ST were evaluated independently by three experienced pathologists and one resident of pathology. The histopathological features studied included elastic fibre distribution in the vascular wall, a smooth muscle arrangement pattern, an internal elastic lamina pattern, fibrinoid necrosis and luminal thrombosis. Agreement analysis was performed using the kappa coefficient. Sensitivity, specificity, positive predictive value (PPV), positive likelihood ratio (PLR) and 95% confidence interval (95% CI) of the useful histopathological features were analysed. Of all 62 biopsies, 28 were cPAN and 34 were ST. Reproducibility between four observers was in substantial agreement (κ = 0.73). Elastic fibre distribution in the vascular wall (κ = 0.68), fibrinoid necrosis (κ = 0.63), an internal elastic lamina pattern (κ = 0.51) and a smooth muscle arrangement pattern (κ = 0.46) showed high specificity and PPV for differentiating between cPAN and ST. The smooth muscle arrangement pattern, internal elastic lamina pattern and elastic fibre distribution in the vascular wall may be obscured when extensive inflammation and necrosis occurs.

CONCLUSIONS

These aforementioned histopathological features are useful in differentiation between cPAN and ST. The Verhoeff-van Gieson (VVG) elastic stain is an important histochemical study for differentiating between cPAN and ST, particularly in cases with extensive inflammation and necrosis.

In vasculitis of small muscular arteries, activation of vessel-infiltrating CD8 T cells seems to be antigen-independent

The etiology of polyarteritis nodosa (PAN) and localized PAN is still unknown, although a T cell-mediated immune mechanism has been considered. CD8 T cells participate not only in the antigen-dependent adaptive immune system, but also in the antigen-independent innate immune system. Non-antigen-activated CD8 T cells express a unique phenotype: granzyme B (GrB) positive /CD25 negative /programmed death-1 (PD-1) negative. The aims of this study were to assess the participation of T cells, especially innate CD8 T cells, in the development of vasculitis. Twenty-eight consecutive cases of skin biopsy specimens with cutaneous vasculitis of small muscular arteries (CVSMA) were retrieved. The series comprises of 21 cases of cutaneous arteritis, three cases of PAN, and four cases of rheumatoid vasculitis. Cases of antineutrophil cytoplasmic antibody-associated vasculitis were excluded. The phenotypes of infiltrating lymphocytes in vasculitis lesions were evaluated by immunohistochemistry. In most cases of CVSMA, the number of CD8 T cells infiltrating the intima was higher than that of CD4 T cells, and significant numbers of GrB-positive cells, which represent activated CD8 T cells, were observed. However, GrB/CD25-double-positive cells, which correspond to antigen-activated T cells, were very few in a small number of cases. Cells positive for PD-1, which is also expressed on antigen-activated CD8 T cells, were not detected. We conclude that a T cell-mediated immune mechanism, involving cytotoxic CD8 T cells, may play a role in the development of CVSMA. Low expression of CD25 in activated CD8 T cells suggests that activation was antigen-independent.

Lymphocytic Thrombophilic Arteritis: A Possible Association with Minocycline

We describe a case of lymphocytic thrombophilic arteritis in a 15-year-old girl who had previously taken minocycline for a year. Cutaneous polyarteritis nodosa and lymphocytic thrombophilic arteritis share many features and may both be triggered by minocycline. There may be a long latency between drug exposure to minocycline and development of disease.

Gangrenous digital infarcts in a severe case of cutaneous polyarteritis nodosa

Cutaneous polyarteritis nodosa (CPAN) is a rare diagnosis which is distinct from polyarteritis nodosa (PAN). PAN is a medium-vessel vasculitis which can affect multiple organs and classically produces microaneurysms in the vasculature. CPAN is limited to the skin mainly affecting small vessels. There is an absence of microaneurysms in CPAN and it does not affect internal organs. However, the histopathological findings on the skin are similar to PAN. CPAN rarely progresses to PAN but relapses more often. We will illustrate a challenging case of a patient with CPAN who developed gangrenous infarcts despite initial immunosuppressive treatment with high-dose steroids and azathioprine. His treatment had to be escalated to intravenous cyclophosphamide which induced disease remission.

Cutaneous polyarteritis nodosa localized to a region of lymphedema secondary to Streptococcus viridans cellulitis and multiple surgeries

Cutaneous polyarteritis nodosa (CPAN) is a chronic, indolent, single organ arteritis that generally presents with lower extremity nodules and/or livedo racemosa, accompanied by malaise and arthralgias. CPAN is often triggered by infection, commonly Group A streptococcal species, and is considered an autoimmune reaction. Scarring from surgery and obliterative lymphangiitis from bacterial cellulitis are the causes of lymphedema. Lymphedematous skin is predisposed to autoimmune disorders. Herein we report a 53-year-old woman who developed CPAN restricted to a localized area of the right upper arm-shoulder that had undergone multiple surgeries, complicated by episodes of Streptococcus viridans cellulitis. Clinically, a 15 cm diameter plaque exhibited violaceous, reticulate margins, subtle papules and nodules and central livedo racemosa. Biopsy showed numerous foci of arteritis in active, subacute and reparative stages. In addition, a broad zone of fibrosis replaced the deep dermis-subcutis zone and harbored numerous dilated lymphatic vessels scar lymphedema. Treatment consisted of high potency topical corticosteroids under occlusion; remission after 3 months therapy and follow-up. CPAN primarily affects the lower legs, a region of frequently affected by phlebolymphedema. This report of CPAN localized to an area of scar lymphedema underscores the importance of lymphatic function in the pathogenesis of CPAN.

Epidemiological, clinical and laboratory profiles of cutaneous polyarteritis nodosa patients: Report of 22 cases and literature review

Cutaneous polyarteritis nodosa (CPAN) is a rare disease that affects small and middle caliber vessels of the deep dermis and subcutaneous tissue and its etiopathology remains yet to be understood.

METHODS

Retrospective review of twenty two cases diagnosed as CPAN and confirmed by skin biopsy over the last 11 years was evaluated in our department.

RESULTS

We found predominance in white woman, mean age of 39.4 years, showing no comorbidities in most of our sample. Mean follow-up time was 58 months. The most frequent cutaneous manifestations were ulcers, livedo racemosa, subcutaneous nodules, atrophie blanche lesions and purpuras; with lower limb involvement in all cases, however other areas were also involved. The main regional symptoms were pain and paresthesia, while systemic complaints were absent in the majority of cases. Mononeuritis multiplex was identified in a quarter of our sample. Most of the laboratory findings were non-specific. There was evidence for previous contact with Mycobacterium tuberculosis in 46.1% of cases which were tested for purified protein derivative (PPD) test. In our patients the disease course was benign and without complications, and systemic polyarteritis nodosa did not develop in any patient.

CONCLUSIONS

An extensive work-up including laboratory tests on autoimmunity and thrombophilic factors and investigation of infectious diseases, especially previous contact with tuberculosis agent, should be part of the CPAN investigation.

Chronic reparative changes in medium-sized vessels in a case of primary cutaneous anaplastic large-cell lymphoma with angioinvasive features and cytotoxic phenotype: new histopathological findings in line with indolent clinical behavior

Angioinvasion/angiodestruction has been reported in a small subset of primary cutaneous anaplastic large-cell lymphomas (PCALCL). Recently, PCALCL with angioinvasive features and cytotoxic phenotype has been characterized as a variant associated with good clinical outcomes despite worrisome histopathologic features. We report a case of PCALCL with angioinvasive features and cytotoxic phenotype associated with reparative changes on the wall of medium-sized vessels involved by the neoplasm, including intimal fibroblastic proliferation and luminal obliteration. This vascular pattern, although previously unreported in PCALCL, is in accordance with the indolent behavior observed in this entity and provides a further link with lymphomatoid papulosis type E.

[Macular lymphocytic arteritis and periarteritis nodosa: A case report showing diagnostic and nosological challenges posed by these two entities]

BACKGROUND

Macular lymphocytic arteritis is a recently described type of cutaneous vasculitis involving vessels of medium size. Authors consider it as a form of polyarteritis nodosa. Herein we report a case of macular lymphocytic arteritis during the course of which periarteritis nodosa appeared.

PATIENTS AND METHODS

A 50-year-old man, with no history other than chronic venous insufficiency of the lower limbs, presented with an asymptomatic eruption involving all four limbs, mainly the lower limbs, and appearing in episodes. Physical examination revealed brown macules, in some cases outlining the configuration of livedo reticularis. Laboratory findings were normal except for the presence of low levels of anticardiolipin activity at diagnosis, which had subsided three months later. Histological examination of the skin biopsy showed lymphocytic arteritis with some histiocytes and neutrophils, as well as an eosinophilic ring of parietal necrosis. Six months later, the patient developed multineuritis, leading to the diagnosis of polyarteritis nodosa. A diagnosis of cutaneous polyarteritis nodosa could also have been made based on the association of cutaneous livedo and locoregional polyneuritis without systemic involvement.

DISCUSSION

The diagnosis of macular lymphocytic arteritis is based upon clinical and histological findings and upon disease progression. This entity seems to belong to the same spectrum as periarteritis nodosa, especially in the cutaneous form. Given the lack of knowledge concerning progression from macular lymphocytic arteritis to nodosa periarteritis, close patient monitoring is called for, as illustrated by our case report.

Levamisole-induced vasculopathy: a report of 2 cases and a novel histopathologic finding

Although cocaine-induced pseudovasculitis and urticarial vasculitis have been reported in the past, levamisole-induced vasculopathy with ecchymosis and necrosis, termed here LIVEN, has only recently been described in association with cocaine use. Levamisole, a veterinary antihelminthic agent used previously as an immunomodulating agent, is present as a "cutting agent" in approximately two-thirds of the cocaine currently entering the United States. Levamisole is believed to potentiate the effects of cocaine and may also be used as a "signature" for tracing its market distribution. Herein, we report 2 cases of LIVEN in patients with histories of chronic cocaine use. In both the cases, a temporal association with neutropenia preceding the eruption was noted. A novel histopathologic finding present only in the second case was the presence of extensive interstitial and perivascular neovascularization. Our 2 cases reaffirm that neutropenia may precede the cutaneous eruption of LIVEN. Case 2 extends the spectrum of histopathologic findings to include the novel phenomenon of neovascularization-hitherto unreported in this entity.

The histological assessment of cutaneous vasculitis

Vasculitis is defined as inflammation directed at vessels, which compromises or destroys the vessel wall leading to haemorrhagic and/or ischaemic events. Skin biopsy is the gold standard for the diagnosis of cutaneous vasculitis, whose manifestations include urticaria, infiltrative erythema, petechiae, purpura, purpuric papules, haemorrhagic vesicles and bullae, nodules, livedo racemosa, deep (punched out) ulcers and digital gangrene. These varied morphologies are a direct reflection of size of the vessels and extent of the vascular bed affected, ranging from a vasculitis affecting few superficial, small vessels in petechial eruptions to extensive pan-dermal small vessel vasculitis in haemorrhagic bullae to muscular vessel vasculitis in lower extremity nodules with livedo racemosa. Skin biopsy, extending to subcutis and taken from the earliest, most symptomatic, reddish or purpuric lesion is crucial for obtaining a high-yielding diagnostic sample. Based on histology, vasculitis can be classified on the size of vessels affected and the dominant immune cell mediating the inflammation (e.g. neutrophilic, granulomatous, lymphocytic, or eosinophilic). Disruption of small vessels by inflammatory cells, deposition of fibrin within the lumen and/or vessel wall coupled with nuclear debris allows for the confident recognition of small vessel, mostly neutrophilic vasculitis (also known as leukocytoclastic vasculitis). In contrast, muscular vessel vasculitis can be identified solely by infiltration of its wall by inflammatory cells. Extravasation of red blood cells (purpura) and necrosis are supportive, but not diagnostic of vasculitis as they are also seen in haemorrhagic and/or vaso-occlusive disorders (pseudovasculitis). Vasculitic foci associated with extravascular granulomas (palisaded neutrophilic and granulomatous dermatitis), tissue eosinophilia, or tissue neutrophilia signal the risk for, or co-existence of systemic disease. This essential histological information coupled with direct immunofluorescence and anti-neutrophil cytoplasmic data and clinical findings enables more precise and accurate diagnosis of localized and systemic vasculitis syndromes.