Not a criteria of a solitary benign pulmonary nodule on chest X-ray
Ans. is 'c' ie Cavitation (Ref Sutton, 6/e, p 316; Harrison, 16/e, p 512, 516 (15/e, p 568))Even looking in a large no. of books including radiology books, I could not get a satisfactory explanation. But still I could give some help on a repeatedly asked topic - Solitary Pulmonary nodule (SPN)"When apt: presents with an asymptomatic SPN (defined as an X-ray density of any shape usually 1 to 6 cm in greatest diameter) a decision to resect or to follow the nodule must be made.Approximately 35% of all such lesion in adults are malignant, most being primary lung cancer; while < 1% are malignant in nonsmokers under 35 years of age.If no diagnosis is immediately apparent the following risk factors would all argue strongly in favour of proceeding with resection to establish a histological diagnosis -a h/o Cigarette smokingage 35 year or oldera relatively large lesionlack of calcificationchest symptomsassociated atelectasis, pneumonitis or adenopathyAt present, only 2 radiographic criteria are reliable predictors of the benign nature of a solitary pulmonary noduleLack of growth over a period of 2 yrs.Certain characteristic pattern of calcification (calcification alone does not exclude malignancy). Calcification patterns which are highly suggestive of a benign lesion -a dense central nidusmultiple punctate focibulls eye (granuloma)popcorn calcification (hamartoma)When old X-ray are not available and the characteristic calcification patterns are absent the following approach is reasonable -Non smoking patients younger than 35 yrs can be followed and any significant growth should lead to its resection."For pts older than 35 yrs and all pts with smoking history, a histological diagnosis must be made." - Harrison 15/e, Size - Masses larger than 4 cm are predominantly primary malignancies. -Sutton, 6/eCavitation - common cavitating lesion are tuberculosis, staphylococcal inf & carcinoma.Peripheral location - The maximum I could get is that Metastasis have predilection for the periphery but they are usually multiple nodules (75%)So much of B.C., but still we are not certain of the answer, but this text will certainly help you for future questions on this imp. topic.Cavitation was the answer of consensus in my circle.
Less than 5cm size
Peripheral Location
Cavitation
Concentric Calcification.
Lung Cancer