Thymoma with osseous metaplasia

A rare case of thymoma with entire-tumor calcification

A 49-year-old woman presented with cough, and chest X-rays showed an abnormal shadow. Chest computed tomography showed an anterior mediastinal 40-mm mass with massive calcification. The patient underwent mediastinal tumor excision performed using video-assisted thoracoscopic surgery. Pathological findings revealed the tumor to be a type B3 thymoma, with massive calcification occupying almost all of the thymoma. Due to high risk of recurrence, we performed completion thymectomy. Pathological findings revealed no remaining thymoma tissue in the residual thymus. Mediastinal tumor with entire calcification could be a candidate for surgical excision.

Thymoma mimicking an aortic aneurysm: always expect the unexpected

Thymic epithelial tumours (TETs) are rare lesions that represent less than 1% of all malignancies in adults. Presentation occurs in three ways: asymptomatic, with local thoracic symptoms or with paraneoplastic symptoms. Heterotopic ossifications are rare histological features in neoplasms and non-neoplastic lesions. Here, we present a 49-year-old male patient with a thymoma type B2 mimicking an aortic aneurysm. Alongside the thymoma, a cholesterol granuloma with unusual ossification features was found as well. This clinical presentation and pathological diagnosis are unusual findings.

Invasive thymoma with multiple ring calcifications and osseous metaplasia: A case report

An 8.0 × 7.0 × 3.0 cm calcified anterior mediastinal mass was found in a 57-year-old man during a regular health checkup. The tumor had invaded the pericardium and phrenic nerve. The Masaoka-Koga classification was stage III. Multiple ring calcifications were present in the gross feature, and osseous metaplasia was observed in the histologic examination. World Health Organization histologic classification of the tumor was type B2. The patient is currently undergoing chemotherapy and radiation therapy to prevent tumor recurrence. To our knowledge, this is the first case of multiple ring calcifications and osseous metaplasia in invasive thymoma.

Thymoma with osseous metaplasia in an adolescent

A 13-year-old girl was incidentally found to have a partially calcified anterior mediastinal mass during the work-up for a left humeral lesion. The resected specimen demonstrated a lymphocyte predominant World Health Organization type B1 thymoma with nodules of metaplastic bone consistent with osseous metaplasia. In addition, she had multiple osteochondromas, a periosteal chondroma of the humerus, a metaplastic osseous pseudotumor of the thigh, and other benign-appearing sclerotic foci, all manifestations of what is likely an autosomal dominant disorder.

Giant ossifying malignant thymoma in a child

We present the first reported case of an ossifying pediatric thymoma. Our patient was diagnosed with a massive thymoma replacing the whole of the left thoracic cavity. Percutaneous biopsy was attempted 3 times followed by an open incisional biopsy and adjuvant chemotherapy. Complete resection required a median sternotomy and a "trap door" thoracotomy after the tumor failed to respond to chemotherapy. Histology confirmed World Health Organization type B1 lymphocyte-rich thymoma, Masaoka stage I, with extensive osseous metaplasia.

Heterotopic ossification: Review of histologic findings and tissue distribution in a 10-year experience

Heterotopic ossification (HO) within tissues involved by a pathologic process is a well-recognized phenomenon. It is most frequently observed in atherosclerotic plaques, in soft tissue around joints, and in the central nervous system. Less frequently, carcinomas and some benign neoplasms will undergo heterotopic ossification. We performed a retrospective review of our experience with HO over a 10-year period to determine the frequency and tissue site distribution of heterotopic ossification. A computerized review of surgical pathology records of approximately 126,000 reports revealed 85 cases in which heterotopic ossification, ectopic bone or metaplastic bone was specifically mentioned in the surgical pathology diagnosis. Twenty-two cases were neoplasms of non-osseous tissues, and 63 cases were non-neoplastic lesions. Immunohistochemical staining for bone morphogenic proteins (BMP) 1, 4, and 6 was performed. Fourteen cases showed staining for BMP-1, 22 cases showed staining for BMP-4, and five cases showed weak staining for BMP-6. HO is a relatively infrequent finding and is more commonly seen in degenerative and reparative conditions than in neoplasms.