Endobronchial metastasis in benign giant cell tumor of bone in a 25-year male -Second case report with literature review.

Sir,

Giant cell tumor (GCT) of bone is a benign but locally aggressive tumor of 20-40 years of age group and typically presents as a large lytic mass at epiphyseal end of long bones.[1] These benign tumors often recur locally and rarely it may metastasize.[2] We herein report a case of GCT of bone with endobronchial metastasis. To the best of our knowledge, only one case[3] of BGCT with endobronchial metastasis has been reported in the literature. The possibility of benign GCT (BGCT) should always be considered in this scenario as early treatment makes a difference in the management of these patients.

A 25-year-old man, unmarried, non-smoker presented with hemoptysis, breathlessness, cough, dull aching bilateral chest pain and history of weight loss for 3 months. There was no history of fever. His respiratory rate was 28 breaths/min and oxygen saturation was 95% while breathing room air. His pulse rate was 104 beats/min and BP was 100/80 mmHg. There was no pallor, clubbing, cyanosis, edema or lymphadenopathy. Cardiovascular examination and abdominal examination were normal. A single hard non-tender bony swelling and deformity over right wrist was present which was attributed by the patient to a traumatic fracture and concurrent surgery 3 years back. A respiratory system examination revealed diffuse bilateral rhonchi. His laboratory values revealed Hb- 12.3 gm%, TLC 8,500/mm3, P72%, L26%, E2% M2%. KFT, LFT and urine report was normal. Mantoux test was negative and PFT revealed restrictive lung disease (FVC 63%). C-ANCA and P-ANCA were also negative. S. ACE level was normal. Sputum and BAL for AFB was negative. Chest X-ray [Figure 1] revealed multiple bilateral round to oval, nodular opacities of homogeneous density, ranging in diameter from 0.5 to 2.0 cm suggestive of cannon ball opacities. HRCT chest revealed bilateral round to oval opacities of homogenous densities suggestive of secondries. X-ray wrist joint showing soap bubble appearance suggestive of GCT of bone. Bronchoscopic examination revealed [Figure 2] rounded hemorrhagic mass like lesion coming out from the right main bronchus occupying almost whole lumen suggestive of either Ca bronchus or benign tumor or metastasis. Histopathology from wrist was diagnostic of GCT of bone. An endobronchial biopsy of lung mass [Figure 3] revealed a BGCT. Final diagnosis of BGCT of bone (osteoclastoma) with benign pulmonary metastases and local recurrence was made. We have followed up the patient for 3 year. There was recurrence of GCT of wrist. Ultimately the patient developed respiratory failure and died 3 year after recurrence of wrist GCT with pulmonary metastasis.

Figure 1

Chest X-ray revealed multiple bilateral round to oval, nodular opacities of homogeneous density, ranging in diameter from 0.5 to 2.0 cm suggestive of cannon ball opacities

Figure 2

Rounded hemorrhagic mass-like lesion coming out from the right main bronchus occupying the whole lumen

Figure 3

Endobronchial biopsy of lung mass revealed a benign giant cell tumor

GCT of bone is a benign but locally aggressive lesion of unknown etiology which occurs chiefly in men between 20 and 40 years after epiphyseal closure. Tumor is an expansile lytic lesion that involves the epiphysis and metaphysis. Tumor may erode and penetrate subchondral bone, articular cartilage and cruciate ligament. Most common site includes epiphysis of distal femur, proximal tibia and distal radius. Other common sites are fibula, sacrum, proximal humerus, distal tibia, bones of pelvis particularly ilium near SI joint and sacral spine. The treatment of GCT is curettage with bone grafting.

Tumors that metastasize are considered “malignant” by definition. However, BGCT of bone is an exception as it behaves in an unpredictable fashion and because of the potential for histologically benign metastases.[4] These benign tumors often recur locally and rarely may even metastasize.[2] The prevalence of pulmonary metastases is approximately 3%.[4] Rarely it metastasizes to other organs[5] like lymph node, liver, soft tissue, brain, mediastinum, scalp, kidney, and penis. According to a study 25% local recurrence of tumors occurs within first 6 months, 97% during the first 2 years and 100% during 3 years. Local recurrence was noted in 83% cases before concurrent pulmonary metastasis. Surgical excision of lung metastasis is now widely accepted as treatment of choice with excellent long-term survival. In nonoperable cases chemotherapy and/or radiotherapy may be alternative treatment. The mortality rate for a patient with GCT metastasis to the lung ranges from 0% to 37%.[5]

In our case bronchoscopic examination revealed rounded hemorrhagic mass like lesion coming out from the right main bronchus, very vascular in appearance. Till date only one case[3] has been reported in literature with similar finding. The most common sites of extrapulmonary primary tumors with endobronchial metastases are colorectal, renal and breast cancer.[3] This case highlights the importance of through clinical examination along with history taking related to other system, and should always advise for bronchoscopy and histopathology in this clinical context.