|Year : 2015 | Volume
| Issue : 3 | Page : 662
Single organ variant of polyarteritis nodosa in epididymis
Ketan Garg, Leelavathi Dawson
Department of Pathology, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi, India
|Date of Web Publication||9-Oct-2015|
A-279, 1st Floor, Shivalik, Malviya Nagar, New Delhi - 110 017
Source of Support: None, Conflict of Interest: None
Polyarteritis nodosa (PAN) is a systemic necrotizing vasculitis that typically affects medium-sized muscular arteries, with occasional involvement of small muscular arteries. Unlike some other vasculitides (e.g. microscopic polyarteritis, Wegener's granulomatosis) PAN is not associated with antineutrophil cytoplasmic antibodies. Patients typically present with systemic symptoms such as fever, weight loss, and malaise. The kidneys, skin, joints, muscles, nerves, and gastrointestinal tract are commonly involved, usually in some combination. PAN can affect any organ, but usually spare the lungs. Clinical variants or subsets of PAN include single-organ disease and cutaneous-only PAN. Scrotal involvement is rarely the first presenting sign. We herein report a case of 36-year-old man who presented with a swelling in the left epididymis, which was surgically removed. The swelling histopathologically showed necrotizing inflammation, fibrinoid necrosis of the medium-sized arteries of the epididymis and was diagnosed to be single organ variant of PAN.
Keywords: Epididymis, fibrinoid, polyarteritis nodosa
|How to cite this article:|
Garg K, Dawson L. Single organ variant of polyarteritis nodosa in epididymis. J Can Res Ther 2015;11:662
| > Introduction|| |
Polyarteritis nodosa (PAN) is a necrotizing vasculitis of small-and medium-sized muscular arteries without glomerulonephritis or vasculitis in arterioles, capillaries, or venules.  It was originally described by Kussmaul and Maier in 1866 as "periarteritis nodosa", and was renamed "PAN" in 1903.  It is a rare disease, with an estimated incidence of 6/100,000/year. Presenting symptoms are usually weight loss (16-66%), fever (36-65%), and myalgias (30-73%).  In this report, we describe a rare case of isolated necrotizing vasculitis of the epididymis presenting as a scrotal mass in an adult who was diagnosed as single organ variant of PAN without any systemic symptoms.
| > Case report|| |
A 36-year-old man presented to our surgical department with nontender swelling in the left epididymal region measuring 2 × 2 × 1 cm that had been noticed since 1 month and was increasing in size. On examination, the swelling was soft to firm. No skin or joint lesions were noted, and the rest of the physical examination was normal. Urinalysis and cultures were negative. A full blood count and liver and kidney functions were normal. Ultrasound imaging of the testis showed a hypoechoic mass that was attached to the tail of the epididymis.
On surgical exploration, the epididymis was thickened, hyperemic and firm in consistency. The testis appeared normal. Excision of the epididymal swelling was done under local anesthesia and was sent to the histopathology department. We received single greyish-white soft tissue bit measuring 1.5 × 1 × 1 cm, which was both cystic and solid on cut section. Histological studies showed normal epididymal tissue with necrotizing inflammation of the medium and small sized vessels. The different stages of acute inflammation and chronic stages of fibrinoid necrosis were seen in the same slide [Figure 1] and [Figure 2]. Few arteries showed degeneration of their walls with deposition of fibrinoid material. No capillaries showed inflammation. At places, ill-formed granulomas containing multinucleate giant cells were seen close to damaged vessel walls [Figure 3]. Phosphotungstic acid hematoxylin stain confirmed the fibrin deposition in the walls of the arteries [Figure 4]. The clinical and histopathological findings suggested isolated epididymal vasculitis.
|Figure 1: Necrotizing inflammation of the medium-sized arteries (H and E, ×100)|
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|Figure 2: Necrotizing inflammation of the medium-sized arteries (H and E, ×400)|
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|Figure 3: Multinucleate giant cells around the damaged arterial walls (H and E, ×400)|
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Rheumatoid factor, antinuclear antibody, antineutrophil cytoplasmatic antibodies, hepatitis B surface antigen, and antibodies to hepatitis C were negative. Chest X-ray, electrocardiogram and fundoscopy were normal. A final diagnosis of a single organ variant of PAN was made.
| > Discussion|| |
Isolated epididymal vasculitis usually occurs as a part of a systemic disease; most commonly PAN and is seen less frequently in other vasculitis such as Wegener's granulomatosis, Henoch-Schonlein purpura, etc., PAN is a disease of young adults and it has been seen that the majority of cases of isolated PAN in adults do not progress to the systemic form.  Our patient had no systemic manifestation. Laboratory tests in our patient showed normal urine and absence of serum auto-antibodies, and chest X-ray was normal. Laboratory data usually is nonspecific and histological analysis of biopsy specimens remains the mainstay of diagnosis in such cases. In our patient, histopathology showed arterial wall involvement and destruction in different stages of the disease at the same time. Few arteries showed acute phase with a mixed infiltrate of neutrophils and mononuclear cells, frequently accompanied by fibrinoid necrosis. Few arteries showed fibrous thickening of the vessel wall in chronic stages. No small vessel involvement was seen. Hence, all stages of activity were seen to coexist characteristically in different vessels as in PAN. Microscopic polyangitis and Wegener's granulomatosis formed a close differential. Microscopic polyangitis was ruled out as it mainly involves capillaries, arterioles and venules and spares out medium and large sized arteries. Wegener's granulomatosis was also ruled out as there were no significant granulomas with geographic patterns of central necrosis or respiratory tract involvement. This presentation of isolated vasculitis of the epididymis without other manifestations, together with the histological findings, supported the diagnosis of isolated PAN in epididymis.
Single organ variant of PAN may not follow the ACR criteria for classic PAN  as it is not a systemic disease. Rare case reports of isolated PAN involving testes have been described. ,,, The histological picture in isolated PAN is similar to that seen in classic PAN, with some minor differences in cases of isolated arteritis, notably the lack of thrombosis, aneurysm formation, or infarction. The etiology of isolated arteritis is unknown. Many forms of arteritis are considered to be mediated by immunological mechanisms. Potentially antigenic material may be localized in the epididymis following trauma or retrograde flow of urine. In our case, there was no history of recent trauma or any urinary symptoms. 
It appears that the majority of cases of isolated PAN in adults do not progress to the systemic form. Thus, it is not surprising that the recommendations in the literature are for either a local excision or a short course of corticosteroids along with adequate clinical and serological monitoring for possible progression to systemic involvement.  In some reported cases, the testicular masses were diagnosed as tumors, and consequently the patient underwent a radical orchiectomy.  PAN, if untreated, has a poor prognosis; death, usually resulting from renal failure or cardiovascular or intestinal complications. Isolated PAN is often asymptomatic and has an excellent prognosis. Thus, it is important that any patient with histological evidence of necrotizing arteritis should have full clinical, hematological, and biochemical investigations to exclude systemic disease because of the clinical differences between classic PAN and isolated form. 
The general condition of our patient was satisfactory after the removal of the epididymal swelling; thus, it was decided to follow the patient without initiating corticosteroid therapy. After 3 months of the follow-up period, he had no clinical or laboratory evidence of disease. In this case, we demonstrated that PAN can present in the epididymis as an isolated finding and can usually be cured with excision of the mass without any postexcision corticosteroids.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]