miliary mottling consists of opacities , between 0.5 to 2 mm in size , in chest radiography . in indian settings , although miliary mottling is more commonly associated with miliary tuberculosis , it can be seen in other conditions such as fungal infections ( histoplasmosis , coccidioidomycosis , cryptococcosis , and blastomycosis ) , sarcoidosis , coal miner s pneumoconiosis , silicosis , hemosiderosis , fibrosing alveolitis , acute extrinsic allergic alveolitis , pulmonary eosinophilic syndrome , and pulmonary alveolar proteinosis .
the incidence of lung cancer is higher in males and peaks between age 55 and 65 years .
the miliary pattern in chest radiography is very rare in patients with primary lung cancer .
here is a rare case of a young , female patient with non - small cell carcinoma of the lung presenting as miliary mottling .
a 28-year - old housewife presented with a history of fever , cough , and chest pain of 15 days duration .  
the patient was apparently normal 15 days prior to admission , when she developed a fever that was gradually progressive , moderate to high grade , and associated with chills .
she also had a pricking type of chest pain , which was central and non - radiating .
the patient was not a diabetic or a hypertensive , and nor was she a known case of ischemic heart disease or tuberculosis . also , she was not a smoker or an alcoholic .
there was no family history of tuberculosis or close contact with tuberculosis .   on examination ,
the patient was afebrile with a pulse of 90 beats per minute and blood pressure of 130/80 mmhg .
general physical examination did not reveal pallor , icterus , clubbing , cyanosis , edema , or lymphadenopathy .
thyroid examination was within normal limits , and respiratory , cardiovascular , abdominal , and central nervous systems were clinically normal .
hemogram revealed a total count of 11,900 /mm . additionally , the differential count was within normal limits and the erythrocyte sedimentation rate ( esr ) was 35 mm / h .
a gram stain showed plenty of epithelial cells , pus cells , gram - positive cocci , and gram - negative bacilli .
thoracic computed tomography ( ct ) revealed a small , mildly enhancing , nodular lesion containing central density involving the posterior basal segment of the left lower lobe with a few enlarged pretracheal , retrocaval , aortopulmonary , and right hilar lymph nodes .
in addition , numerous tiny nodular lesions were scattered in both lung fields and there was no pleural effusion .
chest radiograph , showing miliary mottling thoracic computed tomography , demonstrating a small , mildly enhancing , nodular lesion containing central density ( arrow ) with a few enlarged pretracheal , retrocaval , aortopulmonary and right hilar lymph nodes .
additionally , numerous tiny nodular lesions are scattered in both lung fields , suggestive of tuberculoma with miliary tuberculosis ct - guided fine needle aspiration cytology ( fnac ) was performed to confirm the diagnosis of tuberculosis .
however , fnac sprang a surprise by revealing tumor cells arranged in an acinar pattern with a hyperchromatic nucleus with a background of hemorrhage and necrosis , suggestive of a lower - lobe , left lung non - small cell carcinoma ( adenocarcinoma ) ( figure 3 ) .   computed tomography - guided fine needle aspiration cytology smear , showing pleomorphic tumor cells arranged in an acinar pattern , with a hyperchromatic nucleus with a background of hemorrhage and necrosis , suggestive of non - small cell carcinoma ( adenocarcinoma )
the word  lung cancer  is applied to tumors that arise from the respiratory epithelium ( bronchi , bronchioles , and alveoli ) , whereas mesotheliomas , lymphomas , and stromal tumors are different from epithelial lung cancer .
the incidence of lung cancer is at its highest between ages of 55 and 65 years .
active smoking increases the relative risk of developing lung cancer by about thirteenfold , and long - term passive exposure to cigarette smoke increases it by 1.5 fold . according to the world health organization ( who ) classification , four major cell types constitute 88% of all primary lung neoplasms : squamous carcinomas ; small - cell carcinomas ; adenocarcinomas ; and large cell carcinomas .
individual cell types have distinct natural histories and responses to therapy , and treatment decisions are chiefly made on the basis of whether a tumor is classified as a small cell carcinoma or as one of non - small cell subtypes .
squamous and small cell carcinomas commonly present as a central mass with endobronchial growth , while adenocarcinomas and large cell carcinomas present as peripheral nodules or masses often with pleural involvement .
a subtype of adenocarcinomas called bronchioloalveolar carcinomas grow along the alveoli without invasion and they can present radiologically as a single mass or a diffuse , multi - nodular lesion or even as fluffy infiltrate . our patient was a young , non - smoking female ( 28 years old ) .
when three samples of sputum for afb and the mantoux test proved negative and thoracic ct showed a nodular lesion suggestive of tuberculoma , the patient was subjected to ct - guided fnac , which completely changed the diagnosis to a non - small cell carcinoma of the lung . for further management ,
the literature contains a small number of similar cases reported as miliary never - smoking adenocarcinoma of the lung .
our patient also showed striking similarities to the 5 patients reported by umeki in 1993 inasmuch as they also had non - small cell carcinoma ( adenocarcinoma ) of the lung with miliary metastases to the lung .
the author identified these 5 cases in a consecutive cohort of 630 patients and suggested that the prevalence of miliary phenotype might be approximately 1% in japanese patients .
moreover , he reported a short survival time after the appearance of the miliary lung metastases .  
be that as it may , lung cancer can be seen in individuals who have never smoked .
the most common type of lung cancer occurring in lifetime non - smokers , in females , and in patients belonging to younger age groups is non - small cell carcinoma .
the differential diagnoses of miliary mottling on chest radiography comprise miliary tuberculosis fungal infections ( histoplasmosis , coccidioidomycosis , cryptococcosis , and blastomycosis ) , sarcoidosis , coal miner s pneumoconiosis , silicosis , hemosiderosis , fibrosing alveolitis , acute extrinsic allergic alveolitis , pulmonary eosinophilic syndrome , pulmonary alveolar proteinosis , and hematogenous metastases from the primary cancers of the thyroid , kidney , trophoblasts , and some sarcomas .
however , tissue diagnosis continues to play an important role in establishing the definitive diagnosis .
 miliary mottling on chest radiography is seen in miliary tuberculosis , certain fungal infections , sarcoidosis , coal miner s pneumoconiosis , silicosis , hemosiderosis , fibrosing alveolitis , acute extrinsic allergic alveolitis , pulmonary eosinophilic syndrome , pulmonary alveolar proteinosis , and rarely in hematogenous metastases from the primary cancers of the thyroid , kidney , trophoblasts , and some sarcomas . 
 although very infrequent , miliary mottling can be seen in primary lung cancers . herein , we report the case of a 28-year - old female with chest x - ray showing miliary mottling . 
 thoracic computed tomography ( ct ) features were suggestive of tuberculoma with miliary tuberculosis . 
 ct - guided fine needle aspiration cytology confirmed the diagnosis as lower - lobe , left lung non - small cell carcinoma ( adenocarcinoma ) . 
 it is rare for the non - small cell carcinoma of the lung to present as miliary mottling . 
 the rarity of our case lies in the fact that a young , non - smoking female with miliary mottling was diagnosed with non - small cell carcinoma of the lung . 