A 45-years-old male patient came to the Emergency Room due to a chest pain of a month of evolution, the physical examination was normal. The patient has a history of metabolic syndrome. Cardiac pathology was ruled out. A thoracic computed tomography (CT) scan was performed, where an destructive sternal bone lesion associated with a soft tissue mass located in the upper third of the breastbone was observed (approximate size 96mm×71mm×53mm) associated to a soft tissue mass located at the upper third of the breastbone were found, in addition to suggestive of malignancy bilateral axillary mediastinal adenopathy's (Fig. 1).
Thoracic computed tomography scan shows destructive sternal bone lesion associated with a soft tissue mass (approximate size 96mm×71mm×53mm) with a hypermetabolic lytic lesion at the manubrium-sternal junction, associated to a mass of perilesional soft. tissues, and infiltration of the upper mediastinal fat with a SUV max value of 8.6.
A PET-CT was performed, where a hypermetabolic lytic lesion at the manubrium-sternal junction, associated to a mass of soft tissue, with infiltration of the upper mediastinal fat with a SUVmax value of 8.6 were found (Fig. 1)
A biopsy of the sternal lesion and the soft tissue mass were performed, whose appearance was highly suggestive of IgG4-related disease, because a positive immunohistochemical study for IgG4 plasma cells was clearly present (Fig. 2). Elevated IgG4 levels in peripheral blood were also found. Treatment with dexamethasone was initiated, and a complete clinical response was seen.
IgG4-related disease is an autoimmune systemic disorder that can affect virtually any organ, most often affecting the pancreas, lymph nodes, and salivary glands.1 The lesions have their own histopathological characteristics, mainly infiltration of IgG4 positive plasma cells in the affected tissue; usually an increase of IgG4 serum levels of is also present.2,3
