Chronic expanding thoracic hematoma is a rare disease entity. Affected patients typically have histories of medical or surgical therapy for the treatment of tuberculosis. The majority of reports of chronic expanding hematoma of the thorax have come from Japan.1,2,6-8
Recent literature from the United States also suggests a certain incidence of chronic expanding thoracic hematoma in Western countries.9,10
However, to the best of our knowledge, no such cases have been reported in Korea until now.
Other than the rare entity which originates in the thorax, chronic expanding hematomas can occur in a variety of locations.11
Although most hematomas resolve spontaneously, a few can persist for long periods, forming slowly expanding space-occupying masses. Subdural hematomas are the most widely reported example of expanding hamatomas.11
The pathogenesis of chronic expanding hematomas has yet to be elucidated in any detail. Labadie and Glover12
have theorized that this self-perpetuating expanding process is attributable to the irritant effects of blood and the products of its breakdown, which induce repeated episodes of bleeding from the capillaries in the granulation tissue. Clinically, intermittent episodes of bleeding, probably due to respiratory motion and coughing, may be responsible for progressive increases in the volume of these hematomas. As was seen in our case, in which old blood and necrotic debris without bacteria, including mycobacteria, were detected in the patient's intrapleural lesion, chronic expanding hematomas of the thorax tend to be nonpurulent and usually display no evidence of bacterial infection.1
The most frequent presenting symptom in such cases is dyspnea, usually related to lung compression, or a slowly growing mass in the chest wall, both of which normally develop 30 years or more after treatment for tuberculosis. Radiologically, chronic expanding thoracic hematomas tend to appear as intrathoracic masses. CT findings usually reveal a heterogeneous mass with a wall of variable thickness, which often harbors peripheral regions of calcification.1,10
Surgical resection at an early stage is the treatment of choice in such cases to prevent mediastinal deviation and extrathoracic protrusion. Surgery is also warranted because it is difficult to differentiate this condition from malignancies, such as malignant lymphoma, soft tissue sarcoma, or squamous cell carcinoma.3-5
The surgical procedure conducted should be a complete resection even if the tumor is benign, because incomplete treatment, such as drainage and curettage of the contents, may result in massive bleeding from the hypervascular subcapsular lesion.1
FDG-PET images of chronic expanding hematoma are not widely available. In one case report of a patient with chronic expanding hematoma in the pelvis, an increased FDG uptake in the peripheral rim of the mass was noted and the maximum standardized uptake value was 3.10, suggesting a hematoma associated with a malignant lesion.13
In our patient, FDG-PET images of the lesion revealed central photon defects with focally increased FDG uptake in the anterior lower portion and the presence of a malignant lesion could not be excluded from these findings.
In conclusion, chronic expanding hematoma of the thorax is a very rare condition, but should be considered in the differential diagnosis in cases in which an expanding mass is observed in the thoracic cavity, especially when the patient has a history of tuberculous pleurisy, thoracotomy, or thoracic trauma.