rasmussen 's aneurysm is a less frequently noticed entity usually associated with pulmonary tuberculosis presenting with massive hemoptysis due to involvement of small peripheral pulmonary or bronchial artery by the tubercular cavity or lesion .
involvement of a large central pulmonary artery by metastatic mediastinal nodal lesions is unreported so far . despite the large size ,
a 65-year - old male of primary squamous cell carcinoma left buccal mucosa treated by left composite resection , and modified radical neck dissection 8 months back .
postsurgery local radiation with 25 fractions of 2 grey ( gy ) each completed just 4 months before , presented with generalized weakness and pain right hip region .
there was no history of fall , fever , loss of weight or bleeding from any site .
clinical examination revealed no evidence of disease at the local site and no palpable masses anywhere in the body and there was no neurological deficit .
hematological , bio chemical and metabolic parameters were within normal limits , except mild hypo chromic normocytic anemia .
initial imaging with magnetic resonance imaging of lumbo sacral spine revealed t1 hypointense and t2 hyperintense signal intensities in right sacral ala and iliac bone lesions suggestive of metastatic lesions .
patient was subjected to fluorine 18-fluoro deoxy glucose positron emission tomography / computerized tomography ( f18-fdg ) for restaging and further evaluation .
the primary site of left buccal region showed postoperative status with no morphological or metabolic abnormality .
there was a metabolically active enhancing nodular mass lesion on the dorsum of the tongue measuring 30  19 mm with a standardized uptake value maximum ( suv max ) of 5.77 [ figure 1a ] , similar nodular deposit in the cervical nuchal muscle measuring 22  21 mm with an suv max of 4.82 [ figure 1b ] .
there were multiple bilateral metabolically active necrotic , nodular , sub pleural and parenchymal pulmonary metastasis with associated mild degree pneumothorax [ figure 2 ] .
mediastinum showed multiple metabolically active enlarged lymphadenopathy encompassing bilateral hilar , sub aortic , and para aortic lymphadenopathy which also showed conglomeration and central necrosis .
interestingly there was a large contrast filled cavitary area measuring 66.6  54.8  72.6 mm seen amidst the necrotic lymph nodal mass , devoid of any fdg avidity [ figure 3 ] . on close scrutiny
the radiographic contrast collection was traceable up to one of the adjoining first order branch of left pulmonary artery [ figure 4 ] .
there were multiple metabolically active mixed lytic sclerotic disseminated skeletal metastasis as well [ figure 5 ] . due to his poor physical condition and the extensive disease load .
small asymptomatic unilateral pneumothorax requiring no intervention and the large extravasated contrast being restricted within the confines of the cavitating nodal metastasis explaining the stark absence of hemoptysis , patient was managed conservatively without any active intervention shifting from a curative to palliative intent .
( a ) metabolically active enhancing nodular mass lesion on the dorsum of the tongue ( dotted arrow ) .
( b ) metabolically active nodular deposit in the cervical nuchal muscle ( thick arrow ) axial positron emission tomography / computerized tomography images of chest showing multiple bilateral metabolically active sub pleural and parenchymal pulmonary metastasis ( arrows ) with associated left sided pneumothorax ( dotted arrow ) axial positron emission tomography / computed tomography images of chest showing multiple metabolically active enlarged mediastinal lymphadenopathy with conglomeration and central necrosis ( arrows ) and a contrast filled cavitary area amidst the necrotic lymph nodal mass devoid of any fluoro deoxy glucose avidity ( dotted arrow ) high resolution axial and coronal computerized tomography chest showing the radiographic contrast collection traceable up to one of the adjoining first order branch of left pulmonary artery ( arrow ) maximum intensity projection and coronal positron emission tomography/ computerized tomography images revealing multiple metabolically active mixed lytic sclerotic disseminated skeletal metastasis ( arrows )
erosive pseudo aneurysm of small caliber pulmonary arterial branch caused by an adjoining infiltrating pulmonary lesion is termed as rasmussen aneurysm .
fritz waldemar rasmussen a 19-century danish physician first described the occurrence of dilation of the pulmonary artery in a tuberculous cavity , rupture of which causes hemorrhage and hemoptysis , often massive and life threatening .
other documented causes are atherosclerosis , bronchiectasis , sarcoidosis , trauma , postcardiac catheterization and postnecrotizing pneumonias .
pathogenesis implicated is the progressive weakening of pulmonary arterial wall adventitia and media by granulation tissue , resulting in thinning of the arterial wall and formation of pseudoaneurysm .
the distribution is usually peripheral and beyond the branches of main pulmonary arteries . in the present era of selective catheter angiography , the entity of rasmussen 's aneurysm
is a retrospective detection encountered while addressing suspected bronchial artery erosion being the cause of massive , intractable and life - threatening hemoptysis .
angiographic intervention is warranted to unearth the source of bleeding and simultaneously attempt to embolize the bleeding source from rasmussen 's transformed culprit artery .
our patient had extensive metastasis to skeleton , lungs , muscles , tongue and mediastinal adenopathy with significant necrosis .
one of the aggressive and necrotizing lymphnodal mass has eroded the adjoining pulmonary artery branch , in this case a major branch vessel unlike smaller vessels usually seen in tuberculosis cavities .
the leaked out blood was contained within the necrotic lymph nodal mass which explains the absence of any revealed hemoptysis and a possible emergency bleeding situation despite the large sized extravasation .
conventional sites of aneurysm are peripheral and beyond the branches of main pulmonary arteries , however it was central in this case and involved a larger central pulmonary arterial branch .
reported cases of rasmussen 's aneurysm are the result of infective and chronic tuberculous cavity eroding the adjoining small caliber bronchial / pulmonary artery and none by an aggressive metastatic necrotic nodal mass .
the case also highlights the aggressive , extensive and erosive nature of squamous cell carcinoma metastasis .
rasmussen 's aneurysm is a rare sequel of pulmonary tuberculosis presenting with massive hemoptysis usually involving a small peripheral pulmonary or bronchial artery .
involvement of a large central pulmonary artery by an aggressive necrotizing mediastinal lymph nodal mass is unreported so far .
our case is one such entity of this rarity with walled off collection of a large magnitude contained within the necrotic mass and nonhemoptytic manifestation being an additional associated rarity .
 the authors report an extremely rare occurrence of a massive aneurysm of a major pulmonary artery branch vessel caused by adjacent necrotizing aggressive squamous cell carcinoma metastatic mediastinal nodes . despite the huge size 
 , there was no hemoptysis due to the walling off effect by the necrotic nodes . 