Radiology Quiz

Case history

A 32 year old sports teacher presented via her puzzled general practitioner complaining of a gradual progression of shortness of breath when exerting herself at work. She also had an annoying cough and was uncharacteristically tired. Her only other complaint was of a sore red right eye that kept watering. On examination a small, non-tender lump was noted in the right supraclavicular fossa.

A chest radiograph shown here was taken.

Questions

(1) What radiological abnormalities are present on this film?
(2) What is your differential diagnosis for this abnormality?
(3) What other investigations might you consider to assist the diagnosis?
(4) What is the characteristic histopathology of this lesion? What special test can be done if a tissue sample cannot be taken?
(5) What other areas of the body may be involved?

Answers

(1) Bilateral hilar lymphadenopathy. There is no pulmonary infiltration.
(2) Differential diagnosis: lymphoma and sarcoidosis are the most likely. Others to consider are bronchial carcinoma (although likely to be unilateral), and pulmonary plethora (pulmonary hypertension and left to right cardiac shunt).¹
(3) The chest radiograph shows bilateral enlargement, but does not show any features that allow a definitive diagnosis to be made. Computed tomography of the chest can help differentiate sarcoidosis from lymphoma; in lymphoma the anterior mediastinal nodes are often enlarged. Computed tomography is also useful in showing the interstitial and bronchovascular inflammatory changes of sarcoidosis. Biopsy, either core or fine needle aspiration, will often be necessary to differentiate the two conditions. If a superficial lymph node is found (in up to a third of patients) this may be conveniently biopsied. The lump in this patient's right supraclavicular fossa is likely to be such a lesion. Otherwise, you may need to undertake a bronchoscopic or computed tomography guided transthoracic percutaneous biopsy.
(4) The characteristic finding is of multiple, discrete, non-caseating - that is, it does not contain central necrosis - granulomas. If a biopsy is contraindicated or inappropriate the Kveim-Siltzbach test may be done. It is less sensitive than transbronchial tissue biopsy. A suspension of human sarcoid spleen (prepared under strict laboratory conditions) is injected beneath the skin. Four to six weeks later a punch biopsy is taken of that area and if it contains non-caseating granulomas the test is said to be positive and is likely to be due to sarcoidosis.
(5) Only the more common features are listed:

• Skin: erythema nodosum, lupus pernio, superficial lymphadenopathy
• Heart: cardiomyopathy, conduction abnormalities, pericardial effusion
• Eyes: uveitis (the complaint mentioned in this patient), keratoconjunctivitis sicca (dry eye syndrome).
• Spleen: splenomegaly
• Brain: granulomatous meningitis, brain infarct (from granulomas occluding small vessels)
• Kidney: hypercalcaemic nephropathy
• Muscles and bones: dactylitis, arthralgia

The diagnosis is sarcoidosis. This is a generalised inflammatory disorder characterised histologically by the presence of non-caseating epitheliod granulomas in various tissues and organs. The bilateral hilar lymphadenopathy is caused by granulomas in the hilar lymph nodes.

Barry Kelly, consultant radiologist, Royal Victoria Hospital, Belfast

Ian C Bickle, fourth year medical student, Queen's University, Belfast


studentBMJ 2001;09:129-170 May ISSN 0966-6494

1. Dick E. Chest x rays made easy. studentBMJ 2000;8:358. (October.)