¹Martin Lee, ³Victoria Scott-Lang, ⁴Kaiser Raja, ⁵Sharmishta Sahu

¹Mediclinic Parkview, ²Mohammed Bin Rashid University, ³Genesis Healthcare Centre, ⁴King’s College Hospital, ⁵Healthbay Polyclinic

Background:

Amyopathic dermatomyositis (ADM) is a variant of dermatomyositis (DM) characterized by the presence of pathognomonic skin features of dermatomyositis but without clinical muscle weakness. The ADM is believed to account for about 20% of cases of DM.

Material(s) and Method(s):

We present the case of a 40-year-old lady who presented in May 2020 with a 6 week history of periorbital oedema and a heliotrope rash. She had a past medical history of rectosigmoiditis diagnosed on colonoscopy in 2018 and managed with mesalazine 2g once a day. Blood tests revealed a transaminitis (ALT 372 u/l, AST 201 u/l). Full blood count was normal as were inflammatory markers (ESR 4 mm/hr, CRP 2 mg/dl) and renal function (creatinine 63.9 umol/l). The CK was normal (72 u/l). A non-invasive liver screen including hepatitis B and C, caeruloplasmin, alpha-fetoprotein and anti-mitochondrial antibodies was negative. A liver ultrasound was reported as normal. An ANA was positive and an ENA screen revealed positive RNP-68, S/RNP and anti-smooth muscle antibodies. Atypical pANCA antibodies were also positive. A myositis antibody screen revealed a positive PL-7 antibody. A skin biopsy of the affected area around the eye demonstrated prominent dermal periadnexal and perivascular chronic inflammation composed mainly of lymphocytes and plasma cells consistent with a connective tissue disease. A liver biopsy confirmed autoimmune liver disease (AILD). Tumour markers (CEA, CA 125, and CA 19-9) were normal and a CT scan of the chest, abdomen and pelvis to rule out occult malignancy was normal. Full lung function tests including transfer factor were normal. A diagnosis of PL-7 positive ADM with associated AILD was made.

Results:

The patient’s ADM and AILD were successfully treated with a reducing course of budesonide (6 mg 3 times daily for 4 months reduced to 3 mg twice daily for 4 months then 3 mg daily for 3 months) and mycophenolate mofetil 720 mg twice daily. Currently, 16 months after her initial presentation, the patient’s ADM and AILD are in remission and she remains on mycophenolate mofetil 720 mg twice daily.

Conclusion:

Anti-PL-7 is one of a number of anti-aminoacyl tRNA synthetase (ARS) antibodies that are associated with DM, polymyositis (PM) and ADM. Other anti-ARS antibodies include Jo-1, PL-12, EJ, OJ, KS, ZO and YRS/HA. Antibodies to PL-7 have been reported to be associated with milder muscle involvement than antibodies to Jo-1. Antibodies to PL-7 have been associated with severe interstitial lung disease (ILD). An association been AILD and inflammatory myositis has been reported in the literature but only in a handful of case reports.