Eggshell calcification (lymph nodes)

Eggshell calcification refers to fine calcification seen at the periphery of a mass and usually relates to lamellar lymph node calcification. For similar appearance in the breast, see eggshell calcification (breast).

Terminology

In 1967 Jacobsen and Felson published criteria to help "avoid over-reading of the incidental circumferential concentrations of calcium and to eliminate confusion with the ring shadows of bronchi on end." These criteria were ⁶:

• shell-like calcifications up to 2 mm thick must be present in the peripheral zone of at least two lymph nodes

• the calcifications may be solid or broken

• in at least one of the lymph nodes, the ring-like shadow must be complete

• the central part of the lymph node may show additional calcifications

• one of the affected lymph nodes must be at least 1 cm in its greatest diameter

Pathology

Etiology

In the mediastinum and thorax ^3,4:

• silicosis: 5% patients

• treated lymphoma: (postirradiation Hodgkin disease) usually 1-9 years following treatment

• coal workers' pneumoconiosis (CWP): 1% patients

• sarcoidosis: calcification is uncommon (only 5% of patients) and occurs late in the disease; only rarely does it have an eggshell configuration

• scleroderma

• amyloidosis: rare

• blastomycosis (e.g. pulmonary blastomycosis): rare 

• histoplasmosis (e.g. pulmonary histoplasmosis): rare

Differential diagnosis

For eggshell-like calcification appearances in the thorax consider:

• aneurysms

• parathyroid tumors

• pulmonary arteries in pulmonary arterial hypertension

• thymic cysts

• thyroid tumors and multinodular goiter

See also

• differential of calcified mediastinal lymph nodes