Background: Malignant melanoma (MM) generally presents as a primary neoplasm of the skin, and most MM cases of the respiratory system are metastatic. Primary MM of the lung (PMML) is quite rare, and its diagnosis is relatively difficult. Case presentation: We report the case of a 57-year-old male patient with PMML who denied any history of tumours. His initial complaint was frequent coughs with bloody sputum for 4 days. Chest radiography demonstrated a highdensity shadow in the lower lobe of the right lung, which was suspected to be a large space-occupying lesion on subsequent computed tomography (CT) and to be a hypermetabolic tumour by positron emission tomography-CT. To confirm the diagnosis, exploratory surgery was performed. Finally, we confirmed the diagnosis of PMML. Conclusions: PMML is extremely rare and easily misdiagnosed as lung cancer. Because of its morphological and immunophenotypic variations, the diagnosis of PMML remains difficult. This case report discusses the diagnosis and case management of a patient while referring to the existing literature.

A novel Ce(iii) ion-implanted aluminum-trimesic metal-organic framework (Ce-MIL-96) was synthesized for the first time via alcohol-solvent incipient wetness impregnation. Compared to previously reported Ce-contained adsorbents, the fluoride adsorption performance of the new ion-implanted metal-organic framework demonstrated much higher adsorption capacity and more efficient regeneration of Ce. In a wide pH range of 3 to 10, Ce-MIL-96 maintained constant adsorption performance for fluoride, and the residual Ce and Al in the treated solution were below the safe limits in drinking water. The maximum adsorption capacity of Ce-MIL-96 was 38.65 mg g at 298 K. Excluding the contribution of MIL-96, the maximum adsorption capacity of Ce ions was 269.75 mg g, which demonstrated that the service efficiency of cerium in Ce-MIL-96 is about 6 times that in CeO, nearly 10 times that in Ce-mZrp, and double that in Mn-Ce oxides. There was no significant influence on fluoride removal by Ce-MIL-96 due to the presence of chloride, nitrate, sulfate, bicarbonate or phosphate. Moreover, the adsorption capacity of Ce-MIL-96 remained at more than 70% after nine cycles of adsorption-desorption. Due to this excellent adsorption performance and its regeneration properties, Ce-MIL-96 is a promising adsorbent for the removal of fluoride from groundwater.

Background Acute fibrinous and organizing pneumonia (AFOP) is a very rare form of acute or subacute lung injury, which is characterized by patches of “fibrin balls” distributed within the alveoli. Given the lack of typical clinical manifestations, AFOP is often misdiagnosed as pneumonia, tuberculosis, etc. Definitive diagnosis is obtained from a lung biopsy. Corticosteroids are usually effective. Case presentation We report two cases of patients with histopathological manifestations of AFOP, which were significantly improved after corticosteroid therapy. Previous reports of the clinical and pathological characteristics of AFOP were reviewed to improve clinicians’ understanding of this disease. Conclusions Early identification and diagnosis are very important for AFOP treatment. The prognosis is acceptable after timely and effective treatment.

BACKGROUND Breast cancer is the most common tumor in women, and about one-third of cases develop metastatic disease. However, metastatic breast cancer rarely invades the common bile duct (CBD) directly without involving the liver, and involvement of the gastrointestinal tract is rare. Cases of such metastases pose a particular diagnostic challenge. CASE SUMMARY A 55-year-old female presented to the Department of Gastroenterology with complaint of a 2 mo history of right upper abdominal pain accompanied by pain in the right back, aggravated after eating greasy diet. The patient had received a diagnosis of breast cancer 3 years prior. Physical examination showed obvious superficial protuberant erythema on the left neck and chest skin, with slight tenderness and burning sensation. Endoscopic retrograde cholangiopancre-atography showed an obstruction at the end of the CBD. Histopathology of the CBD and symptomatic skin biopsies showed positivity for cytokeratin 7 and trans-acting T-cell-specific transcription factor breast cancer biomarkers. A cancer embolus was also found in the skin vasculature. Accordingly, the diagnosis of breast cancer metastases to the skin and biliary ducts was made. A plastic biliary sent was placed, which relieved the right upper abdominal pain and protected against unnecessary hepatectomy surgery. CONCLUSION Although rare, biliary metastasis should be considered in patients with bile duct stenosis and a history of breast cancer.