Rare cystic lung disease in patients presenting with abdominal mass.

Sir,

Lymphangioleiomyomatosis (LAM) is a rare cystic lung disease that primarily affects women and occurs in two forms, sporadic and in association with tuberous sclerosis (TSC).[1] Thoracic involvement is manifested as bilateral lung cysts, recurrent pneumothoraces, chylothoraces, or occasionally hemoptysis and obstructive airway disease. Initial presentation with extrapulmonary features such as abdominal pain and mass is rare.[2] Hereby, we report two cases of LAM whose initial symptoms were due to abdominal mass proved to be angiomyolipoma (AML) of the kidneys.

CASE 1

A 26-year-old nulliparous female presented with acute abdomen and shock for which she had to undergo emergency laparotomy. Intraoperatively, a large well-circumscribed glistening yellow right suprarenal mass with areas of hemorrhage was discovered, which was successfully removed [Figure 1a]. Histopathology was consistent with AML and revealed variable amounts of adipose tissue, smooth muscle, and thick-walled blood vessels. High-resolution computed tomography (HRCT) chest showed the presence of multiple variable sized cysts uniformly scattered bilaterally and normal intervening lung parenchyma [Figure 1b]. Spirometry findings were as follows: forced expiratory volume in 1 s (FEV1) = 3.25 L (90% predicted), forced vital capacity (FVC) = 3.52 L (88% predicted), and a FEV1/FVC = 92%. Diffusion capacity of carbon monoxide (DLCO) was 92% predicted. Skin examination was normal and magnetic resonance imaging (MRI) brain revealed no lesions.

Figure 1

(a) Right renal angiomyolipoma (gross specimen postexcision). (b) High-resolution computed tomography chest images of Case 1 showing multiple variable sized cysts uniformly scattered in both lungs. (c) Computed tomography abdomen showing bilateral renal angiomyolipomas with fat densities, tortuous vessels, and pseudoaneurysm (white arrow). There is also the presence of perinephric hematoma (black arrow). (d) High-resolution computed tomography image of Case 2 showing bilateral lung cysts

CASE 2

A 50-year-old multiparous female presented with left flank pain. She had anemia at presentation and ultrasonography revealed large bilateral renal masses with internal hyperechogenecities. Computed tomography (CT) abdomen showed the presence of fat densities, tortuous vessels, and pseudoaneurysm arising from interlobar renal artery and perinephric hematomas on the left side [Figure 1c]. Coil and glue embolization of the pseudoaneurysm was done to control hemorrhage. A detailed clinical evaluation was initiated after stabilization. Clinical examination revealed the presence of adenoma sebaceum. CT thorax revealed multiple variable sized thin-walled cysts scattered throughout the lung parenchyma bilaterally [Figure 1d]. There were no nodules, reticulations, or ground glass opacities. MRI of the brain was normal. Pulmonary function test revealed a FEV1 of 1.32 L (70% predicted), FVC of 1.54 L (64% predicted), FEV1/FVC ratio of 86%, and a DLCO of 52% predicted.

The diagnosis in the 1st patient was sporadic LAM with right renal AML. Her FVC and DLCO were normal; hence, treatment with sirolimus was deferred. The diagnosis in the 2nd patient was TSC-LAM as she had bilateral renal AML and adenoma sebaceum. Sirolimus was started in her as she had a reduced FVC and DLCO. Close monitoring of the lung function was planned and the future risks of pneumothorax were explained at the time of discharge.

Sporadic LAM is an extremely rare condition affecting approximately 5 in 1,000,000 adult women. In TSC, LAM occurs in 30%–40% of adult females and exceptionally in men and children.[3] AMLs are more common and often bilateral in TSC-LAM as compared to the sporadic form. HRCT chest reveals multiple usually 2–5 mm but occasionally up to 30 mm sized thin-walled cysts evenly distributed throughout the lung fields surrounded by normal lung parenchyma. Nodules, reticulations, and ground glass attenuation are rare. Pneumothoraces, pleural effusion, and mediastinal adenopathy may be concomitantly present. Lung biopsy reveals multiple cysts and multifocal nodular proliferation of immature smooth muscle cells and perivascular epithelioid LAM cells which are positive on human melanoma black-45 staining. Serum vascular endothelial growth factor-D has been recently proposed to be a highly specific test for LAM.

The proposed diagnostic criteria for a definite diagnosis are compatible HRCT features with either characteristic histopathology or any of the extrathoracic findings, namely, AML (histological or radiologically confirmed), chylous effusion/ascites, lymphangioleiomyoma of the lymph nodes, or definite or probable TSC.[4] Both our cases met the criteria for definite diagnosis in the absence of lung biopsy as both had a compatible HRCT features and AMLs. In addition, adenoma sebaceum was also present in the 2nd case which indicated a diagnosis of TSC. Sirolimus, an inhibitor of mammalian target of rapamycin, is the preferred treatment in those with abnormal or declining lung functions and symptomatic chylous effusions.[5] Therapeutic drug monitoring is recommended to minimize the adverse events.

CONCLUSION

LAM is an extremely rare cystic lung disease which commonly occurs in association with renal AMLs and may be associated with TSC. Diagnosis is usually made by characteristic radiological and clinical criteria in the absence of lung biopsy. Treatment with sirolimus in selected cases may prevent the disease progression and worsening of lung function.

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Conflicts of interest

There are no conflicts of interest.