A 63-year-old man was analyzed for platypnea-orthodeoxia syndrome (POS). A complete obstruction due to bronchial carcinoma was found in the left main bronchus with bronchoscopy. After left sided... Show moreA 63-year-old man was analyzed for platypnea-orthodeoxia syndrome (POS). A complete obstruction due to bronchial carcinoma was found in the left main bronchus with bronchoscopy. After left sided pneumonectomy POS resolved completely. Historical reports suggest increased shunting through the left lung could occur in the upright position caused by decreased compression of the left pulmonary artery due to the central bronchial carcinoma. Partially absent hypoxic vasoconstriction was confirmed in this case and suggests (without a relevant shunt through a patent foramen ovale) this 'historical' hypothesis could explain the POS due to increased shunting in the upright position in this patient. Show less
Tumour-to-tumour metastasis is very unusual and has been defined as a tumour metastasis into another histologically different tumour. It is extremely rare in bone. We report a case of lung squamous... Show moreTumour-to-tumour metastasis is very unusual and has been defined as a tumour metastasis into another histologically different tumour. It is extremely rare in bone. We report a case of lung squamous cell carcinoma metastasized to an enchondroma in the femur of a patient with Ollier disease. A 60-year-old female had a history of a poorly differentiated squamous cell carcinoma of the lung. She underwent a video-assisted thoracoscopic lobectomy, and a follow-up MRI scan showed three lesions in the left distal femur and proximal tibia, which were initially interpreted as metastasis on radiology. Resection of the left proximal tibial lesion was performed, and the pathological findings were consistent with enchondroma with no evidence of metastasis. Subsequent curettage of lesions in the distal left femur revealed metastatic poorly differentiated carcinoma with foci of hyaline cartilage, which was most consistent with metastatic carcinoma in a pre-existing enchondroma. The MRI films were re-reviewed. Characteristic MRI features of enchondroma were found in the lesion in the left proximal tibia and one of the lesions in the left distal femur, while the features of the other lesion in the left distal femur included cortical destruction and extensive oedema in surrounding soft tissue, which were consistent with a malignant tumour. In addition, the enchondroma in the lateral condyle showed blurring and irregular inner margin and adjacent bone oedema, which likely represents a co-existing metastatic tumour and enchondroma. The difference in lineage was confirmed by immunohistochemistry. The final diagnosis was metastatic poorly differentiated carcinoma of the lung into a co-existent enchondroma. The diagnosis can be challenging and could be easily overlooked both radiologically and histologically. Thorough clinical and radiological information is critical for the diagnosis, and despite a very unusual event, awareness of the tumour-to-tumour metastasis phenomenon can avoid an inaccurate diagnosis by the pathologist, therefore preventing inappropriate clinical intervention. Show less
