Thymoma exhibiting spontaneous regression with developing myasthenia gravis: A case report

Abstract

Spontaneous regression (SR) of thymoma is rare. A 44‐year‐old man with right chest pain underwent computed tomography (CT), which showed an 11.0 cm mass in the anterior mediastinum and right pleural effusion. He refused surgery and was sent home without medication and additional treatment. One year later, the mass had regressed to 5.5 cm, and the right pleural effusion had disappeared. He was then lost to follow‐up. Four years after the initial visit, he presented with diplopia and fatigue. A significant increase in his anti‐acetylcholine receptor antibody levels led to myasthenia gravis (MG) diagnosis. CT revealed a regressed mediastinal mass (3.0 cm). After extended thymectomy, histologic analysis confirmed a thymoma type B2, Masaoka stage IIa. The SR was due to intratumoral infarction. This report is the first to describe MG developing during SR. Anterior mediastinal tumors undergoing SR should be differentiated from thymomas and MG perioperative development should be considered.

Spontaneous Regression of a Thymoma with Mild Pleural Effusion: A Case Report

“…Nonetheless, SR of thymoma without therapy is a rare phenomenon, with some cases witnessing SR upon treatment with corticosteroids [4,5] . The mechanism in which thymomas spontaneously regress remain unclear, with several reports suggesting that SR could be due to extensive necrosis and vascular compromise or absorption of intratumoral components [2][3][4] . In our case, histological interpretation of the biopsied specimen was a challenge due to extensive necrosis, fibrosis, and cystic degeneration.…”

“…The cause of necrosis itself has not been clearly determined, though, one study stated that rapid tumor growth could result in massive necrosis due to increased internal pressure [4] . Generally, thymomas are asymptomatic except those associated with myasthenia gravis in approximately 20-30% of cases [2] . Moreover, almost all cases of thymomas witnessing SR in past reports have been associated with symptoms ranging from fever, chest pain and shortness of breath with findings of pleural effusion, consistent with our report [2][3][4] .…”

“…Generally, thymomas are asymptomatic except those associated with myasthenia gravis in approximately 20-30% of cases [2] . Moreover, almost all cases of thymomas witnessing SR in past reports have been associated with symptoms ranging from fever, chest pain and shortness of breath with findings of pleural effusion, consistent with our report [2][3][4] . These clinical findings associated with elevation of serum inflammatory markers are mainly consistent with extensive necrosis [4] .…”

“…Thymoma is considered the most common neoplasm arising from the thymus gland, accounting for the majority of neoplasms related to the anterior mediastinum in adults after the age of 40 [1,2] . Thymomas can occur in association with various autoimmune diseases such as Myasthenia Gravis (MG), which potentially account for approximately 20-30% of all thymomas [2] . The phenomenon of spontaneous thymoma regression without therapy is rare, with very few cases reported in previous literature [2][3][4] .…”

“…Thymomas can occur in association with various autoimmune diseases such as Myasthenia Gravis (MG), which potentially account for approximately 20-30% of all thymomas [2] . The phenomenon of spontaneous thymoma regression without therapy is rare, with very few cases reported in previous literature [2][3][4] . This is a report of an uncommon and rare case of spontaneous regression (SR) of a large thymoma in an adult patient.…”