The Ranke complex: incidental finding at CT

Clinical History

A 67 year-old male patient was submitted to our institution to perform a chest CT for staging of a rectum neoplasia.

Imaging Findings

A 67 year-old male patient was submitted to our institution to perform a chest CT for staging of a rectum neoplasia. On the chest CT we found a 1 cm nodule in the anterior segment of the left upper lobe (figure 1), with irregular and ill-defined margins (figure 2), associated with a calcified, ipsilateral hilar lymph node (figure 3). Follow-up chest CT, six months later, showed no changes of this lesion. This findings were compatible with a sequel of tuberculosis, the Ranke complex.

Discussion

Inhaled tubercle bacilli initially evoke a focal, non specific alveolitis that converts to a tuberculosis–specific inflammatory focus (Ghon focus). Spread of tubercle via the draining lymphatics may lead to enlargement of regional lymph nodes. In the great majority of cases this primary complex (Ghon focus and regional lymphadenitis) heals with fibrosis and may calcify (1, 2). Ghon focus appears as a round opacity 3-10mm in diameter showing flocculent or homogenous calcification, usually located in the peripheral lung. It may be accompanied by flocculent calcification of the ipsilateral hilar lymph nodes representing a healed primary complex (the Ranke complex). Occasionally, lymphangitic stranding connecting the primary focus with the hilar lymphadenitis forms a dumbbell-shaped opacity (1, 2). This finding correspond to a previous tuberculosis infection with no significant meaning.

Differential Diagnosis List

Final Diagnosis

Ranke complex

URL:	https://www.eurorad.org/case/5346
DOI:	10.1594/EURORAD/CASE.5346
ISSN:	1563-4086