INTRODUCTION: Pulmonary hyalinizing granuloma (PHG) is a rare lung disease characterized by presence of single or multiple lung nodules. The disease is often asymptomatic and diagnosis requires histopathologic confirmation. PHG generally carries a good prognosis. Significant amelioration of respiratory symptoms is often seen with corticosteroids CASE PRESENTATION: A 40-year-old, housewife, with no known comorbids, presented with complaints of cough and shortness of breath for around 10 months. She reported that cough is mostly non-productive, associated with shortness of breath even on mild activity. She also mentioned low-grade fever with fatigue but no weight loss. She had a 10 pack years history of smoking. She denied joint pains, skin rash or ulcers. She had no family history of TB or lung cancer. On physical exam, her respiratory rate was 20 bpm, and SpO2of 99% on room air with no digital clubbing. There were normal vesicular breath sounds on chest auscultation. Chest X-Ray (fig. 1) showed bilateral multiple rounded opacities. CT chest (fig. 2A, 2B) revealed multiple nodules and masses of variable shapes and sizes. Investigations showed ANA positivity with fine speckled pattern but Anti-dsDNA, RA factor and ENA profile were negative. Bronchoscopy and BAL was offered but she refused. She then underwent CTguided biopsy (fig. 3A,3B,3C) that showed cores of fibrocollagenous tissue with dense keloid like collagen arranged in whorls with interspersed histiocytes and lymphocytes. Special stains including congo red, AFB, Periodic acid schiff diastase(PASD) were negative. She was diagnosed as Pulmonary hyalinizing granuloma. Marked clinical response was seen with corticosteroids within 3 weeks of initiation of treatment.DISCUSSION: PHG was first reported in 1964 by Benfield. The occurrence of this disease is linked to an exaggerated immune response to any infectious or autoimmune processes. Lhote et al. published a case series of PHG in 2016 and performed a detailed analysis of 135 cases of PHG published between 1964 and 2015. The results revealed that median age of presentation is usually 44 years with male gender predominance and the most common presenting symptom was cough being 44%. Conditions associated with PHG were wide in number including infections in 14.1%, autoimmune diseases in 12.1%, tumors in 4.4% and various other causes. CT-guided percutaneous biopsy of lesions is required to confirm the diagnosis. Radiographic improvement in the nodules was more frequent in patients treated with corticosteroids than patients without treatment ( 42.1% and 4.4 % respectively).CONCLUSIONS: PHG remains a unique nodular lung disease. It is a great mimicker of pulmonary metastases and tuberculosis. Hence this case signifies the histopathologic confirmation in all such cases where tuberculosis remains an endemic disease and a high probability of metastatic disease should not distract the clinician from rarities

INTRODUCTION: Pulmonary Sarcomatoid carcinomas (PSC) are rare, poorly-differentiated variants of Non-small cell lung cancers (NSCLC) that comprise 0.3-3% of all primary lung neoplasms. Diagnosis of PSC mainly relies on light microscopy while Immunohistochemical (IHC) panel lacks definitive role for diagnostic confirmation CASE PRESENTATION: A 60-year-old Afghan male, construction worker, presented through ED with 4 years history of intermittent chest pain, shortness of breath, cough and low-grade fever. He was a never smoker. He denied family history of TB and lung cancers. On physical exam, his respiratory rate was 28 bpm with oxygen saturation 87% on room air and decreased breath sounds on right side of the chest. His Chest X-ray (Fig 1 ) showed right sided diffuse infiltrates and opacification. CT chest (Fig 2A , 2B) showed circumferential nodular soft tissue encasement of right lung, likely pleural based with volume loss. CT-guided biopsy was performed. Microscopic examination (Fig3A, 3B, 3C, 3D) showed a biphasic neoplastic lesion composed predominantly of epithelioid to spindle shaped, moderately pleomorphic, hyperchromatic to vesicular nuclei, prominent nucleoli and eosinophilic to clear cytoplasm and a minor component exhibiting glandular architecture. An IHC panel was performed that showed diffuse positive expression of Cytokeratin (CK) AE1/AE3, CAM 5.2 and TLE-1 in both neoplastic components. Cytokeratin 7 and 19 positivity was seen only in glandular component. Negative markers included BerEp4, TTF-1, Napsin-A, Synaptophysin, Desmin, Inhibin, CDX-2, Hep-Par1 and Calretinin. Cytogenetic for translocation t (X; 18) was negative for synovial sarcoma. He was diagnosed as Sarcomatoid carcinoma. He preferentially wanted to be treated in his country so his outcome remains unknown DISCUSSION: SC of lung are defined as de-differentiated NSCLC with both sarcoma, and sarcoma-like differentiation. World Health Organization has divided SC into 5 subtypes including Spindle cell carcinoma, Giant cell carcinoma, Pleomorphic carcinoma, Carcinosarcoma and Biphasic pulmonary blastoma. Majority of patients are elderly, smokers, presenting with nonspecific symptoms and a peripheral mass with well-defined margins. Prognosis is dismal. Lucas et al. study concluded the limited utility of IHC after carrying out a panel that included pan-cytokeratin, CK5/6, calretinin, WT1, Thrombomodulin and Smooth muscle actin. Baldovini et al. highlighted that CK-7 is a sensible marker for spindle/giant cell component and TTF-1 carries higher sensitivity than Napsin-A for sarcomatoid carcinomas. Chromosomal translocation t (X; 18) has been seen in >90% synovial sarcomas. CONCLUSIONS:In our opinion, the combination of relevant clinical history, radiologic imaging, appropriate immunohistochemical markers and cytogenetics are key in differentiating closely related sarcomatoid carcinomas, true sarcomas and sarcomatoid mesotheliomas