Yet another pulmonary manifestation of tuberous sclerosis.

Sir,

We read a recent article titled “Sudden onset of dyspnea in a woman with skin lesions and lung cysts”[1] in pictorial quiz section of your esteemed journal with great interest. The authors have described lymphangioleiomyomatosis causing pneumothorax in a female with tuberous sclerosis. We would like to present yet another unusual pulmonary manifestation of tuberous sclerosis.

A 52-year-old female patient presented to the casualty department with complaints of severe pain in the right lumbar region for the duration of two days. Imaging (ultrasound followed by computed tomography) demonstrated the presence of bilateral renal angiomyolipomas [Figure 1] with intratumoral bleed on the right side. General physical examination revealed the presence of adenoma sebaceum on the face [Figure 2]. Computed tomography of the brain showed multiple calcified foci at the gray-white matter junction and periventricular region.

Figure 1

Coronal noncontrast computed tomography scan of abdomen: Bilateral kidneys (arrows) are replaced by multiple fat containing masses suggestive of angiomyolipomas

Figure 2

Adenoma sebaceum: Multiple erythematous papules on the nose and cheek representing angiofibromata

The patient also complained of dry cough with breathlessness for a period of two years. The respiratory system examination demonstrated the presence of bilateral crepts. Radiograph of chest [Figure 3] and computed tomography [Figure 4] demonstrated the presence of multiple nodules in bilateral lung fields. The nodules were well defined, randomly distributed with peripheral and upper lobe predominance. Few small thin walled cysts were seen in the right upper lobe. Calcified nodules were seen in the bilateral upper lobes likely representing the sequela of the old infection. The presence of bilateral renal angiomyolipomas and adenoma sebaceum was diagnostic of tuberous sclerosis complex (TSC). The imaging findings of the lung in a patient with TSC were consistent with multifocal micronodular pneumocyte hyperplasia (MMPH).

Figure 3

Radiograph of chest in anteroposterior projection: Multiple nodules are seen in bilateral lung fields. Ill-defined calcified opacities are seen in bilateral upper zones

Figure 4

Axial computed tomography image in the lung window at the level of carina: Multiple, small, randomly distributed, well defined nodules in bilateral lung fields. These nodules show peripheral and upper lobe predominance

Until recently, lymphangioleiomyomatosis (LAM), a hamartomatous cystic lung disease, was the only reported pulmonary radiologic manifestation of TSC. This represents a hamartomatous cystic lung disease, observed in 1-2.3% of TSC patients.[2] MMPH is an extremely rare pulmonary manifestation of tuberous sclerosis complex. It was first described by Popper et al. in 1991.[3] Less than 40 cases have been reported in the literature till date. This condition is seen in both males and females with equal frequency. It represents benign hamartomatous proliferations of type II pneumocytes along with alveolar septa and fibrous thickening, increased elastic fibres and aggregates of alveolar macrophages. The clinical manifestation of isolated MMPH includes dyspnoea, cough and mild to moderate hypoxemia. The clinical course in non progressive and treatment is not required. These are usually benign with no malignant potential.[4]

MMPH occurs more frequently in patients with TSC than with LAM and usually not seen in absence of both. It manifests as multiple, diffuse pulmonary nodules on the chest roentgenogram. High resolution computed tomography (HRCT) demonstrates nodules 1-8 mm in diameter that are diffusely scattered. They show random distribution with peripheral and upper lobe predominance.[5] The radiological differentials include military granulomatous infections, langerhans cell histiocytosis and hematogenous metastasis.

In summary, the present case is presented to familiarize the clinicians with a rather unusual pulmonary manifestation of tuberous sclerosis.