Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


Fasciitis Is a Common Lesion of Dermatomyositis Demonstrable Early after Disease Onset by En Bloc Biopsy Combined with Magnetic Resonance Imaging.

Yoshida2,  Ken, Kurosaka2,  Daitaro, Joh1,  Kensuke, Takahashi2,  Eigo, Hirai2,  Kenichiro, Noda2,  Kentaro, Ukichi2,  Taro

Division of Pathology, Sendai Shakai Hoken Hospital
Division of Rheumatology, Department of Internal Medicine, Jikei University School of Medicine, Tokyo, Japan

Purpose:

To investigate the incidence of fasciitis in dermatomyositis (DM), and to analyze the process of myositis progression.

Methods:

En bloc biopsy combined with Short tau inversion recovery or fat-suppressed T2-weighted magnetic resonance imaging (MRI) was performed on fourteen patients with newly diagnosed adult-onset DM. Vascular inflammation score (VIS) was defined as the number of aggregates of >=50 inflammatory cells infiltrating around a small blood vessel or vessels per 4 mm2 area of tissue. Total vascular inflammation score (TVIS) was defined as the summation of VIS in three fields with the most remarkable perivascular infiltrates. Fasciitis was defined as TVIS of the fascia >=3 to exclude very mild inflammation. The grade and distribution of perivascular inflammatory changes were evaluated in the fascia and muscle using TVIS. En bloc biopsy was also performed on six patients with other rheumatic diseases including three patients with polymyositis (PM). These subjects constituted a comparison group. Immunohistochemistry was performed to identify T lymphocytes (CD3), CD4+ cells, CD8+ cells, B cells (CD20, CD79a), and macrophages (CD68).

Results:

In all patients with DM, MRI revealed abnormal hyperintensity in the fascia and in marginal sites of the muscle predominantly over central sites. In Case 11, abnormal hyperintense areas were detected on the first MRI in the fascias, and on the second MRI two months later, the hyperintense areas had progressed from the fascias to marginal sites of the muscles. En bloc biopsy revealed fasciitis evidenced by inflammatory infiltrates around the fascial small blood vessels in most of the patients with DM. However, inflammatory infiltrates around the intramuscular small blood vessels were not detected in four patients with DM. In those who underwent en bloc biopsy earlier than two months after the appearance of muscle symptoms, TVIS of the fascia was significantly higher than TVIS of the muscle. In contrast, in those who underwent en bloc biopsy at two months or later, TVIS of thefascia did not differ significantly from TVIS of the muscle. Immunohistochemistry showed that CD3+ T lymphocytes, CD4+ cells and CD20+ B cells were mainly present among inflammatory cells. The CD4/CD8 cell ratio was >1 in almost all specimens from the patients with DM. In any one of the patients with other rheumatic diseases, MRI revealed no significant hyperintense areas in the fascias and none of specimens from other rheumatic diseases histopathologically revealed fasciitis.

Conclusions:

Fasciitis was histopathologically confirmed in most of the patients with adult-onset DM and recognized as a common lesion that appears early after the onset of muscle symptoms in DM. Our results suggest that the fascial microvasculature is the primary site of inflammatory cell infiltration in DM. The results of MRI suggest that inflammation in myopathy accompanying DM progresses from the fascia into the muscle. Muscle symptoms such as myagia in DM may be attributed to fasciitis if muscle biopsy reveals no myositis. Fasciitis may be a lesion specific to DM rather than to PM.

To cite this abstract, please use the following information:
Yoshida, Ken, Kurosaka, Daitaro, Joh, Kensuke, Takahashi, Eigo, Hirai, Kenichiro, Noda, Kentaro, et al; Fasciitis Is a Common Lesion of Dermatomyositis Demonstrable Early after Disease Onset by En Bloc Biopsy Combined with Magnetic Resonance Imaging. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :921
DOI: 10.1002/art.28689

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