Eggshell Calcification, Hilum



Eggshell Calcification, Hilum


Robert B. Carr, MD



DIFFERENTIAL DIAGNOSIS


Common



  • Silicosis


Less Common



  • Sarcoidosis


  • Treated Lymphoma


Rare but Important



  • Fungal Infection


  • Scleroderma


  • Amyloidosis


ESSENTIAL INFORMATION


Key Differential Diagnosis Issues



  • Eggshell calcification usually relates specifically to lymph nodes


  • Peripheral nodal calcifications < 2 mm in thickness


  • May be continuous or broken ring of calcification


  • May or may not be associated with internal calcifications


  • Etiology of this calcification pattern is unknown


  • Should be distinguished from calcified aneurysm or pulmonary artery


Helpful Clues for Common Diagnoses



  • Silicosis



    • Due to chronic inhalation of silica dust


    • Usually requires at least 10 years of exposure


    • Disease will continue to progress despite discontinuation of exposure


    • Eggshell calcifications also occur with coal worker’s pneumoconiosis (CWP)


    • CWP often coexists with silicosis, and differentiation is not possible with imaging


    • Mining occupations: Heavy metals and rock


    • Silica is ingested by macrophages, which break down and damage lung parenchyma


    • Multiple centrilobular and subpleural nodules


    • Nodules may be calcified


    • Progressive massive fibrosis



      • Coalescence of silicotic nodules


      • Results in mass > 1 cm in size


      • More common in upper lobes


      • May become necrotic and cavitate


      • Rarely occurs in pure CWP


    • Areas of emphysema often surround nodules


    • Disease predominates in upper and posterior lungs


    • Silicosis predisposes to tuberculosis infection


    • Acute silicoproteinosis: Due to acute exposure of a large amount of silica dust; imaging appearance resembles pulmonary alveolar proteinosis


    • Caplan syndrome: CWP with associated rheumatoid arthritis; may see large necrobiotic nodules


Helpful Clues for Less Common Diagnoses



  • Sarcoidosis



    • Systemic disease of unknown etiology


    • Pulmonary disease predominates in most patients


    • Usually presents as restrictive lung disease


    • Commonly involves hilar, right paratracheal, and aortopulmonary window lymph nodes


    • Eggshell calcification is uncommon manifestation


    • Numerous lung nodules in perilymphatic distribution


    • Nodules may become calcified


    • Chronic disease may result in patchy upper lobe fibrosis with honeycombing


    • Radiographic stages



      • Stage 0: Normal appearance


      • Stage 1: Hilar &/or mediastinal lymphadenopathy without visible lung disease


      • Stage 2: Hilar &/or mediastinal lymphadenopathy with visible lung disease


      • Stage 3: Lung disease without lymphadenopathy


      • Stage 4: Chronic lung fibrosis


    • Associated with systemic disease



      • Cardiac: Conduction anomalies, myocardial infiltration


      • Ophthalmologic: Uveitis, retinitis


      • Neurologic: Basal meningitis, myelopathy, uveoparotid fever


      • Dermatologic: Alopecia, erythema nodosum



      • Endocrine: Hypercalcemia, hyperprolactinemia


  • Treated Lymphoma



    • Lymphoma may involve any lymph node within chest


    • Untreated nodes rarely calcify


    • Treatment with radiation &/or chemotherapy may result in calcification


    • Calcification occurs in 2-8% of cases post treatment


    • Rarely induces eggshell pattern


    • Post-treatment calcification may suggest better prognosis, especially with Hodgkin disease


Helpful Clues for Rare Diagnoses



  • Fungal Infection



    • Endemic fungi live in soil


    • Organisms are geographically distributed



      • Histoplasma capsulatum: Midwestern and eastern USA


      • Coccidioides immitis: Southwestern USA and northern Mexico


      • Blastomyces dermatitidis: Midwestern and eastern USA


    • Imaging findings



      • Histoplasmosis: Multifocal consolidation, lymphadenopathy, scattered calcified and noncalcified nodules


      • Coccidioidomycosis: Consolidation, lymphadenopathy, nodules with cavitation, calcification uncommon


      • Blastomycosis: Consolidation, miliary disease, ARDS


    • Eggshell calcification is most common with histoplasmosis but rare overall


  • Scleroderma



    • Most patients have interstitial fibrosis in UIP or NSIP pattern


    • Lower lungs and subpleural regions usually affected


    • Look for esophageal dilation, which is commonly present


    • Eggshell calcifications have been reported but are rare


  • Amyloidosis

Tags:
Aug 8, 2016 | Posted by in CARDIOLOGY | Comments Off on Eggshell Calcification, Hilum

Full access? Get Clinical Tree
Get Clinical Tree app for offline access