대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Mesenchymal hamartoma

Radiologic Findings

CT scans reveal an about 5cm-sized mass in the right lower posterolateral chest wall, between the latissimus dorsi muscle and right 8th rib posterolateral arc. The mass is encapsulated. It has a central calcific density with surrounding fat, and soft tissue or fluid density posteriorly and laterally. The calcific portion is fragmented into smaller pieces in the peripheral portion. The largest calcific portion has a lobulated margin and looks ossified. The lesion is measured 4.8x2.5cm on axial scan.

Brief Review

A mesenchymal hamartoma of the chest wall is a very rare benign chest wall tumor. Mesenchymal hamartomas are not considered true neoplasms and are composed of maturing, proliferating normal skeletal elements, with no propensity for invasion or metastasis. It typically present in neonates or infants. The most common modes of clinical presentation of MHCW are as a chest wall mass in infancy, with or without respiratory distress.

Typically, these lesions arise from the central portions of one or several ribs. Computed tomography best demonstrated the matrix mineralization, seen in 100% of lesions, with the mineralization appearing chondroid alone in 79%. Hemorrhagic cystic regions (secondary aneurismal bone cyst areas) also were seen with CT (fluid levels in 64% of lesions), although T2-weighted MR images were superior in demonstrating this feature in 80% of cases.

Histologically, the lesion is composed of cartilage, smooth muscle, and respiratory epithelium forming a disorderly mass. The stroma consists of oval or spindle mesenchymal cells with no atypia or abnormal mitotic activity. Osteoclast-like giant cells in the vicinity of blood-filled cysts resemble aneurysmal bone cysts.

In this case, at surgery, the mass was a freely movable hard mass beneath the latissumus dorsi muscle. There was no adhesion, no invasion. The extirpation of the mass was done. He has had no evidence of recurrent disease for two years

References

1. Groom KR, Murphey MD, Howard LM et al. Mesenchymal hamartoma of the chest wall: radiologic manifestations with emphasis on cross-sectional imaging and histopathologic comparison. Radiology. 2002;222 (1): 205-11. doi:10.1148/radiol.2221010522

2. Kentaro Okamoto, Yukiko Tani, Takeshi Yamaguchi, et al. Asymptomatic Mesenchymal Hamartoma of the Chest Wall in Child With Fluorodeoxyglucose Uptake on PET/CT—Report of a Case. Int Surg. 2015 May; 100(5): 915–919. doi: 10.9738/INTSURG-D-14-00083.1

Please refer to

Case 760

Keywords

chest wall, benign tumor, hamartoma,