Sarcoidosis: This is often considered the most likely diagnosis for bilateral hilar enlargement due to its relatively high prevalence and characteristic radiographic findings. Sarcoidosis is a systemic granulomatous disease that frequently presents with bilateral hilar lymphadenopathy.

Lymphoma: Both Hodgkin's and non-Hodgkin's lymphoma can cause bilateral hilar enlargement due to lymph node involvement. The presence of systemic symptoms such as weight loss, fever, and night sweats can support this diagnosis.
Tuberculosis: Although more commonly associated with unilateral findings, tuberculosis can cause bilateral hilar lymphadenopathy, especially in its early stages or in immunocompromised patients.
Histoplasmosis: This fungal infection can lead to bilateral hilar enlargement, particularly in endemic areas. It often presents with symptoms similar to those of tuberculosis.

Lymphangitic Carcinomatosis: This condition, characterized by the spread of cancer through the lymphatic vessels in the lungs, can cause bilateral hilar enlargement. It is crucial to identify this condition due to its poor prognosis and the need for prompt oncologic intervention.
Wegener's Granulomatosis (Granulomatosis with Polyangiitis): This vasculitic disease can present with a variety of pulmonary and systemic symptoms, including bilateral hilar enlargement. Early diagnosis is critical due to the potential for severe organ damage.

Castleman Disease: A rare lymphoproliferative disorder that can cause bilateral hilar lymphadenopathy. It is often asymptomatic but can be associated with systemic symptoms.
Berylliosis (Chronic Beryllium Disease): An occupational lung disease caused by exposure to beryllium, which can lead to granulomatous disease similar to sarcoidosis, including bilateral hilar enlargement.
Silicosis: Although typically associated with upper lobe fibrosis, silicosis can cause hilar lymphadenopathy, especially in advanced stages.