Pleural involvement in Non-Hodgkin Lymphoma (NHL) is well documented, but primary pleural lymphomas are extremely rare, occurring mostly in immunosuppressed patients or associated with chronic pleural inflammation. Nevertheless, the pathogenesis and therapeutic approaches to counteract primary pleural lymphomas are still matter of debate. The authors present the clinical case of an 81-year-old female with respiratory and constitutional symptoms. A valvular heart disease and bilateral pleural effusion were known. The study carried out showed a large right pleural effusion; the fluid analysis was compatible with Diffuse Large B-cell Lymphoma (DLBCL), and two lymphomatous masses with pleural origin were found at the ipsilateral hemithorax. Primary pleural lymphoma was considered and chemotherapy was initiated with a good response and evolution. The authors report this remarkable clinical case because of its rarity, its excellent clinical evolution and the absence of an immunodeficiency context.

Tuberculous pericarditis is a rare extra-pulmonary manifestation of tuberculosis observed mainly in developed countries. It usually presents with concomitant tuberculous infection at a different site and, due to the lack of clinical specificity, diagnosis can be difficult. Thus, a diagnostic delay is frequent, entailing increased morbidity and mortality. The authors present a case of disseminated tuberculosis with predominantly cardiac symptoms with multiple negative samples for Mycobacterium tuberculosis, which evolved to constrictive pericarditis. With this case report, the authors emphasize the demand for a high index of suspicion for achieving a diagnosis and the importance of a multidisciplinary approach.

Postobstructive pneumonia is a pulmonary infiltrate distal to a bronchial obstruction. It presents a diagnostic challenge, and full attention should be on recognition of this entity, identify, and treating the obstructive lesion and secondary infection. In adults, malignancy is the main cause; however, others etiologies must be investigated.

Pyelocaliceal obstruction is a diagnostic challenge, and it is important to identify the obstruction cause. Some patients present extra‐renal compressive masses that need further imagiologic investigation and a biopsy, to establish the diagnosis.

Forestier disease is a condition characterized by calcification and ossification of ligaments and entheses particularly affecting axial skeleton. Diagnosis is difficult and mandates a high suspicion level, but unexpensive and accessible examinations like a simple radiography might provide useful diagnostic clues in these challenging clinical scenarios and improve clinical assistance.

Hemophagocytic lymphohistiocytosis poses a diagnostic dilemma due to the absence of specific clinical and laboratory findings, especially in adults. Despite greater recognition of the disease, secondary idiopathic forms are still reported.