Talcosis



Talcosis


Jud W. Gurney, MD, FACR





Key Facts


Imaging Findings



  • Inhalational



    • Diffuse fine-granular nodularity with high attenuation perihilar PMF


    • Aggregation of nodules into PMF (identical to silicosis)


    • International Labor Office “B” opacity type “p”


    • Pleural and diaphragmatic plaques identical to those from asbestos


    • Inhalational: Nodules in lymphatic distribution (centrilobular and subpleural)


  • Intravenous



    • Ground-glass opacities (probably due to nodules below resolution of scanner) usually exceeds profusion of nodules


    • PMF all zones


    • Basilar panlobular emphysema in intravenous Ritalin abusers


    • Intravenous: Nodules perivascular distribution (centrilobular) with occasional tree-in-bud opacity


Top Differential Diagnoses



  • Silicosis


  • Sarcoidosis


  • Metastatic Pulmonary Calcification


  • Cellulose Granulomatosis


Clinical Issues



  • Corticosteroids may stabilize PMF in intravenous talcosis


  • Slow progression even without further inhalational exposure







Axial NECT shows perihilar fibrosis to be of high density image, typical of progressive massive fibrosis from talcosis.






Coronal CECT shows an upper lung zone PMF image. Even with fibrosis, the lungs are hyperinflated due to Ritalin abuse. Note the enlarged main pulmonary artery image.


TERMINOLOGY


Abbreviations and Synonyms



  • Illicit drug use, simple pneumoconiosis, complicated pneumoconiosis, progressive massive fibrosis (PMF), IV drug abuser’s lung


Definitions



  • 4 forms: 3 inhalational, 1 intravenous



    • Inhalation pure talc (talcosis)


    • Inhalation talc and silica (talco-silicosis)


    • Inhalation talc and asbestos (talco-asbestosis)


    • Intravenous illicit drug use


IMAGING FINDINGS


General Features



  • Best diagnostic clue



    • Diffuse fine-granular nodularity with high attenuation PMF


    • Basilar panlobular emphysema in intravenous abusers of methylphenidate (Ritalin)


  • Patient position/location



    • Inhalation: Nodules in upper lung zones



      • Progressive massive fibrosis in all zones


    • Intravenous: Nodules diffuse



      • Emphysema: Lower lobes


      • Progressive massive fibrosis perihilar


  • Size: Nodules pinpoint in size


  • Morphology: Ground-glass opacities usually greater in extent than definable nodules


CT Findings



  • NECT: Progressive massive fibrosis typically of high attenuation, highly suggestive of talcosis


  • HRCT



    • Inhalational



      • Centrilobular and subpleural nodules, may calcify


      • International Labor Office “B” opacity type “p”


      • Aggregation of nodules into PMF (identical to silicosis)


      • Architectural distortion adjacent to PMF


      • PMF all zones


      • Pleural and diaphragmatic plaques identical to those from asbestos


      • Pleural thickening can sometimes be dramatic


      • Lymphadenopathy may be of higher attenuation



    • Intravenous



      • Centrilobular (fine granular appearance) nodules (< 1 mm diameter)


      • Ground-glass opacities (probably due to nodules below resolution of scanner) usually exceeds profusion of nodules


      • Nodules spare emphysematous lung, but otherwise uniform throughout lung


      • Emphysema may be upper lung zone or predominantly lower lung zone (even in absence of smoking)


      • Proclivity of Ritalin for severe lower lobe panacinar emphysema


      • Ritalin may result in severe lower lung zone panacinar emphysema alone without nodularity


      • PMF perihilar


Radiographic Findings



  • Radiography



    • Inhalational



      • Multiple tiny (pinpoint) miliary nodules


      • Predominantly upper lung zones


      • May evolve into progressive massive fibrosis


      • Lower zone reticular opacities and pleural changes in those with asbestos contamination


      • Enlarged hilar lymph nodes with eggshell calcification (especially in silico-talcosis)


    • Intravenous



      • Miliary “pinpoint” nodules


      • No zonal predilection


      • Occasionally lymphadenopathy


      • PMF in perihilar regions


      • Calcification in PMF usually not recognized on radiographs


      • Emphysema, either centriacinar (upper lung zones) or panacinar (lower lung zones)


      • Pulmonary artery hypertension in severe disease


    • Talc pleurodesis



      • Often used for pleurodesis due to intense inflammation induced by talc


      • Pleural thickened with irregular deposits of calcification in most dependent lung (dorsal) due to settling of talc in supine position


Imaging Recommendations



  • Best imaging tool: HRCT for characterization of interstitial lung disease and detection of high attenuation conglomerate masses


DIFFERENTIAL DIAGNOSIS


Sarcoidosis



  • No occupational exposure, PMF less likely


  • Nodules usually larger and tend to cluster (“galaxy” sign)


  • Peribronchovascular distribution of nodules


Metastatic Pulmonary Calcification



  • No progressive massive fibrosis


  • Emphysema if present admixed with ground-glass opacities or consolidation


  • Centrilobular nodules larger and mulberry shape and tend to cluster


  • Predominantly disease of upper lung zones


Silicosis



  • Occupational history


  • Nodules tend to be larger than talc


  • PMF usually more cephalad in upper lung zones and not high in attenuation


  • Talc and silica may be admixed together


  • Pleural plaques not seen


Cellulose Granulomatosis



  • Cellulose filler in oral medications


  • Cellulose particles trapped in arterioles leading to granulomatous reaction


  • HRCT: Centrilobular nodules and tree-in-bud pattern


  • No progressive massive fibrosis


Amyloidosis



  • Also may be related to IV drug abuse



  • Nodular form: Multiple small scattered pulmonary nodules


  • May calcify but calcification in small nodules rare


Neurofibromatosis



  • Upper lobe bullae


  • Lower lobe reticular interstitial fibrosis


  • Cutaneous and skeletal stigmata of neurofibromatosis


Amiodarone Toxicity



  • Used to treat tachyarrhythmia


  • Accumulates in lung and liver


  • Focal areas of consolidation randomly distributed


  • Focal lung abnormalities and liver of high attenuation due to drug, which contains 3 iodine molecules

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Sep 20, 2016 | Posted by in RESPIRATORY IMAGING | Comments Off on Talcosis

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