Atelectasis

A 70-year-old woman presented with a 1-month history of increasing dyspnea and a nonproductive cough. She had a history of bronchial asthma, hypertension, carotid endartectomy, diverticular disease, and osteoarthritis. She had no other systemic symptoms and had not smoked for many years. Medications included aspirin, bendrofluazide, inhaled fluticasone, and albuterol.

On clinical examination, she was afebrile with a pulse rate of 90 beats/min and a BP of 140/100 mm Hg. A small mobile lymph node was palpable in the anterior triangle close to the left sternomastoid insertion. There was mild stridor, and wheezing was heard over the left upper lobe. Spirometry showed an FE[V.sub.1] of 1.6 L/min and FVC of 2.3 L.

Chest radiography showed left upper lobe collapse, bulky paratracheal nodes, and a faint opacity at the right apex (Fig 1). Her CBC count, biochemical profile, tumor markers, and serum angiotensin-converting enzyme levels were normal or negative. The C-reactive protein level was 17 mg/L (reference range, 0 to 8 mg/L), and file [[beta].sub.2]-microglobulin level was 5.9 mg/L (reference range, 1.2 to 2.4 mg/L).

[FIGURE 1 OMITTED]

Bronchoscopy showed extrinsic compression of the left upper lobe bronchus just distal to its branching from the secondary carina. There was a minor mucosal abnormality, but findings on bronchial biopsy and brushing samples were negative on two occasions. Fine-needle aspiration findings were non-contributory. A video-assisted thoracoscopic lung biopsy from the left upper lobe and a biopsy of a mediastinal lymph node were performed.

What is the diagnosis?

Diagnosis: Left upper lobe atelectasis secondary to nodal sarcoidosis

Lobar atelectasis in this age group is commonly due to malignancy; initially, this was thought to be the most likely diagnosis. However, histologic examination demonstrated subpleural noncaseating epitheloid granulomata (Fig 2) complete with both Langerhan and foreign body-type giant cells. The granulomata were mainly around the bronchovascular bundles and interlobular septae. Stain results for fungi and tuberculosis were negative. The biopsy of the lymph nodes showed extensive fibrosis and focal calcification but also some small noncaseating epitheloid granulomata. The nodal capsule remained intact. The histologic features were those of sarcoidosis.

[FIGURE 2 OMITTED]

DISCUSSION

Lobar atelectasis is unusual in sarcoidosis. In 1985, Rockoff and Rohatgi (1) cited only 17 reported cases. The putative mechanisms are compression by enlarged adjacent lymph nodes, endobronchial sarcoidosis, or a combination of both. Given the frequency of lymph node enlargement in patients with sarcoidosis, the incidence of atelectasis is surprisingly low. Unlike tuberculosis, the capsular integrity of lymph nodes is usually preserved in patients with sarcoidosis and the nodules remain discrete and well delineated. Matting of lymph nodes and subsequent scarring is rare and seldom causes anatomic distortion of adjacent bronchi. Although endobronchial sarcoid is common, it is rarely of sufficient magnitude to cause bronchial stenosis or atelectasis. (1)

The majority of cases of sarcoid-related atelectasis involve the middle or lower lobes, although upper lobe collapse has been described occasionally. (2-7) The cause of this predominance is likely to be due to the local variation in lymph node density, namely the aggregation of lymphoid tissue surrounding the middle and lower lobes. An additional factor is the acute angle of origin of the middle lobe bronchus from the mainstem, which is thought to compound its vulnerability. (8)

The elevated [[beta].sub.2]-microglobulin level in this case is compatible with sarcoidosis but is nonspecific. It is a light-chain component of class I major histocompatibility complex present in most nucleated cells, but 50% of serum levels are derived from lymphocytes. Elevations in [[beta].sub.2]-microglobulin levels occur in conditions of heightened lymphoid activity (eg, lymphoproliferative disorders) or when clearance is reduced as in renal failure. There is conflicting evidence about the correlation of serum angiotensin-converting enzyme levels with [[beta].sub.2]-microglobulin; however, if the [[beta].sub.2]-microglobulin level reflects total sarcoid granulomatous burden, as has been speculated, (9) it has proved disappointing as a way of monitoring disease activity.

This patient initially failed to recall that 35 years previously she had undergone serial radiographs for an undiagnosed radiologic abnormality shortly after her sister had died of sarcoidosis. Subsequent recovery and review of old radiographs showed left hilar lymph node enlargement that had varied over the years but had never been associated with any major parenchymal abnormality. Following the diagnosis of sarcoidosis, the patient was treated with oral prednisolone, which resulted in a rapid resolution of symptoms and radiologic abnormalities. Following this, the prednisolone dosage was titrated downwards, and the patient remains asymptomatic receiving 10 mg/d.

REFERENCES

(1) Rockoff SD, Rohatgi PK. Unusual manifestations of thoracic sarcoidosis. AJB Am J Roentgenol 1985; 114:513-528

(2) Katsuros T. Middle lobe atelectasis in sarcoidosis, Prax Pneumol 1971; 25:479-482

(3) Munt PW. Middle lobe atelectasis with sarcoidosis: report of a case with prompt resolution concomitant with corticosteroid administration. Am Rev Respir Dis 1973; 108:357-360

(4) Onizuka K, Mori K. Pulmonary sarcoidosis associated with middle lobe syndrome: report of a case [in Japanese]. Rinsho Hoshasen 1975; 20:503-508

(5) Poe RH. Middle-lobe syndrome due to sarcoidosis with pleural effusion. N Y State J Med 1978; 78:2095-2097

(6) Goldenburg GJ, Greenspan RH. Middle lobe atelectasis due to endobronchial sarcoidosis with hypercalcemia and renal impairment. N Engl J Med 1960; 262:1112-1116

(7) Witko J, Strazzela WD, Safirstein BH. Upper lobe collapse due to endobronchial sarcoidosis. AJR Am J Roentgenol 1990; 154:897-898

(8) Brock RC. The anatomy of the bronchial tree. 2nd ed. London, UK: Oxford University Press, 1954

(9) Mornex JF, Biot N, Pacheco Y. [[beta].sub.2]-Microglobulin levels in serum and bronchoalveolar lavage fluid from patients with sarcoidosis. In: Chretien J, Marsac J, Saltiel J, eds: Sarcoidosis. Pads, France: Pergamon Press, 1983; 372-377

* From Castle Hill Hospital (Drs. Aye and Greenstone), Cottingham, East Yorkshire; and Hull Royal Infirmary (Dr. Campbell), Hull, United Kingdom.

Manuscript received March 8, 2001; revision accepted May 23, 2001.

Correspondence to: Michael A. Greenstone, MD, Medical Chest Unit. Castle Hill Hospital, Cottingham, East Yorkshire, HU16 5JQ, United Kingdom; e-mail sternes@sternes.demon.co.uk

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