5-5-Nodular pattern

1-Multiple rounded opacities 1-10 mm (miliary opacities).

2-Causes:

-TB.

-Metastases(thyroid and breast).

-Alveolar cell carcinoma.

-Sarcoidosis.

-Pneumoconiosis.

3-If you find bilateral miliary nodules with evidence of multiple mediastinal lymphadenopathy, look to the shape of the lymph nodes,

If they are bulky and emulgemated with homogenous appearance, it should be lymphoma.But if you see it discrete and homogenous, this can give you diagnosis of sarcoidosis.

If the lymph nodes is necrotic, our differential diagnosis is metastases against TB infection, search for history of primary and ask for laboratory investigation to differentiate between them.

4-In diagnosis of sarcoid disease, nowadays they consider presence of pulmonary nodules are more pathognomonic than lymphadenopathy.

5-Difference between the nodules of pneumoconiosis and that of the miliary TB is that  the former is calcified heavily as stones(seen in mediastinal window).

6-Progressive massive fibrosis is the end stage of pneumoconiosis where nodules coalesce together to form masses which have a characteristic appearance of two big masses surrounding upper mediastinum(spot diagnosis), here the more the fibrosis, the less the number of nodules.

6-Pulmonary lung microlithiasis:

-Dense sharply defined nodules.

-Greater in lung bases.

-Black pleura sign: unaffected pleura between lung and ribs(other sign is that you cannot see the heart from the opacity).