Case report of anti‐transcription intermediary factor‐1‐γ/α antibody‐positive dermatomyositis associated with gastric cancer and immunoglobulin G4‐positive pulmonary inflammatory pseudotumor

Abstract

Dermatomyositis is a rare connective tissue disease often associated with internal malignancy and interstitial pneumonitis. Serologically, various auto-antibodies (Ab) are associated with dermatomyositis. Anti-transcription intermediary factor-1-γ/α (TIF-1-γ/α) Ab was recently identified as an auto-Ab and was observed mostly in cancer-associated dermatomyositis. IgG4-related disease is a newly described entity characterized by increased serum IgG4 levels and IgG4-positive plasma cell infiltration with fibrosis in organs such as the pancreas and parotid gland. IgG4-related disease also includes inflammatory pseudotumors in various organs. We report herein a 59-year-old Japanese man who had dermatomyositis complicated with a gastric cancer and an IgG4-related pulmonary inflammatory pseudotumor. He manifested typical classical Gottron's papules on the fingers, V-sign erythema on the chest, flagellate erythema on the back, nail fold bleeding and facial erythema. Serum levels of anti-TIF-1-γ/α Ab were positive as assessed by immunoprecipitation assay. He also had bilateral swelling of the parotid gland, and an excised specimen of the lung showed inflammatory pseudotumor with IgG4-positive plasma cells. As far as we know, this case is the first to report the association of IgG4-related disease and TIF-1-γ/α-positive dermatomyositis. Further accumulation of such cases is required to elucidate the mechanism of this association.

A case of inflammatory pseudotumor of the lung presenting as polymyalgia rheumatica

“…There have been rare reports of inflammatory pseudotumors within the cervicothoracic spine in patients with established polymyalgia; however, none specifically reported in the lung of a patient with PMR only. Inflammatory pseudotumors have been described in patients with other rheumatologic conditions, such as dermatomyositis and granulomatosis with polyangiitis . Lesions are reported both in a multifocal pattern, as well as solitary findings described in the brain, esophagus, stomach, liver, spleen, lymph nodes, salivary glands, testes, breast, soft tissues, and skin .…”

“…Inflammatory pseudotumors have been described in patients with other rheumatologic conditions, such as dermatomyositis and granulomatosis with polyangiitis . Lesions are reported both in a multifocal pattern, as well as solitary findings described in the brain, esophagus, stomach, liver, spleen, lymph nodes, salivary glands, testes, breast, soft tissues, and skin . Although rare, inflammatory pseudotumors of the lung should be considered as part of the differential diagnosis when a pulmonary lesion is discovered in a patient with an unexplained inflammatory condition.…”

“…When evaluated microscopically, it is typically discovered that inflammatory pseudotumors consist of a variety of cellular elements, making histological diagnosis difficult. They are generally composed of fibrous tissue, inflammatory cells, and characteristically large numbers of plasma cells . The plasma cells are polyclonal in nature with immunoglobulin G predominance, specifically IgG‐4 .…”

“…4,8 The plasma cells are polyclonal in nature with immunoglobulin G predominance, specifically IgG-4. 4,6,8,12 In the lung, these lesions may be parenchymal or endobronchial. Considered cellularly benign, they rarely invade the mediastinum, but can impinge on nearby structures.…”

“…Polymyalgia rheumatica (PMR) is a relatively common inflammatory condition that generally occurs in patients 50 years and older, characterized by aching and morning stiffness specifically in the shoulder and pelvic girdles . Though inflammatory pseudotumors have been reported in other rheumatologic conditions, we present a case of an inflammatory pseudotumor of the lung in a patient with clinically appearing PMR.…”