intralobar pulmonary sequestration ( ilps ) with an anomalous systemic arterial blood supply represents a mass of nonfunctioning parenchyma surrounded by visceral pleura ( 1 , 2 ) . unlike extralobar sequestration , radiographically demonstrated calcification in the ilps has been reported in some case series , but primary sequestration associated with typical hamartoma signs is really rare and has been described only once ( 3 , 4 ) . in this report , we present a rare case of giant hamartoma originated from primary ilps in a 39-year - old woman who had intracranial cholesteatoma . a 39-year - old woman with an abnormal mass in the right cerebellopontine angle was referred to neurosurgery department of our hospital . a giant mass in the right thoracic cavity was detected accidentally by x - ray in a routine preoperative screening process . subsequent thoracic computed tomography scan demonstrated a complex lesion ( size 15.1  12.3  15.7 cm ) occupying more than two - thirds of the thoracic cavity on the right side . the blood supply to the area of the lesion was from a systemic artery arising from the abdominal aorta , with venous drainage through the inferior pulmonary vein , suggesting an ilps ( figure 1 a - 1c ) . three months later , an open thoracic surgery for the intrathoracic lesion was performed under general anesthesia . intraoperatively , lesion appeared hypervascular , because of abundant systemic vascularization ( figure 2 a ) . the massive lesion was compressing the right lung and there was no communication between the tracheobronchial tree and sequestered lesion . based on the findings of 3d ct angiography , we explored the aberrant artery at the bottom of the chest and carefully ligated it with an absorbable silk suture . after the pulmonary ligament had been completely divided , the lower pulmonary vein was found to be widened . the lesion was adherent to adjacent pulmonary vein branches and was not easily dissected . to avoid major intraoperative blood loss , pathologic analysis showed a predominant fatty differentiation with fibroblastic , chondroid and osseous differentiation making the rest ( figure 2b - 2d ) . the postoperative recovery was uneventful and the patient was discharged from the hospital on the eighth postoperative day . ilps is usually diagnosed later than extralobar sequestration ( els ) , being found in childhood or adulthood when the patient presents with an infection ( 5 ) . up to 15% of patients , particularly in adult population , are asymptomatic when the sequestration is discovered incidentally ( 6 ) . in our case , the sequestration surrounded by visceral pleura , characteristically receives its blood supply from a systemic artery with venous drainage through pulmonary veins and was consistent with ilps . the lesions of ilps may be solid , fluid or hemorrhagic or may contain mucus . primary sequestration associated with typical hamartoma signs final histology was pulmonary hamartoma with predominantly adipose and cartilage differentiation , which is an unusual complication originated from primary sequestration . pulmonary hamartoma is a rare lung neoformation , usually symptomless and discovered incidentally , of a probable dysontogenetic origin with prevailing cartilaginous tissue and adult onset age ( 7 ) . in a series of 24 patients , gabrail and zara ( 8) concluded that pulmonary hamartomas are frequently accompanied by other developmental abnormalities and benign tumors . however , the entity described ( pulmonary hamartoma syndrome ) seems to be distinct from well - established multiple hamartoma syndrome ( cowden s syndrome ) . many interesting features characterize the case report : histopathological nature of the pulmonary hamartoma , the typical vascular structure related to intrapulmonary sequestration and intracranial cholesteatoma as shown by neurosurgery operation . . the combination of sequestration , hamartoma and cholesteatoma may be only an incidental combination , but this could indicate both possibilities as hamartomatosis change on underlying sequestration or sequestration associated with hamartomatosis syndrome .