Multifocal skeletal tuberculosis is a very rare manifestation of tuberculous infection. The multiple bone lesions of multifocal skeletal tuberculosis are difficult to differentiate from metastasis, even when performing 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (FDG PET/CT) or magnetic resonance imaging (MRI). A 25-year-old man presented with an abnormal chest X-ray. Radiologically, there were extensive osteolytic lesions on the skull, along the entire spine and on the ribs and both iliac bones, suggesting a diagnosis of bone metastasis. On FDG PET/CT, intensely increased F-18 FDG lesions were observed. A bone biopsy with a microbiologic study revealed a tuberculous infection. Follow-up PET/CT performed after treatment showed marked improvement in the extensive FDG uptake lesions.

We report a case of a chronic hemodialysis patient who developed hypermagnesemia due to an overdose of magnesium-containing laxative and paralytic ileus resulting in colonic perforation. Despite intravenous calcium infusion and daily hemodialysis, the patient developed ischemic colitis and intestinal perforation. Colonic perforation accompanied with hypermagnesemia in hemodialysis patients has rarely been reported. This case suggests that hypermagnesemia should be considered in renal failure patients as this can result in life-threatening events despite prompt treatment.

Imatinib mesylate is a targeted therapy that acts by inhibiting tyrosine kinase of the bcr-abl fusion oncoprotein, which is specific to chronic myeloid leukemia (CML), and the c-transmembrane receptor, which is specific to gastrointestinal stromal tumors. Interstitial pneumonitis is a rare adverse event of imatinib therapy. It is clinically difficult to distinguish from infectious pneumonia, which can frequently occur due to the underlying disease. The standard treatment for imatinib-induced pneumonitis is to discontinue the medication and optionally administer corticosteroids. However, there are a few cases of successful retrial with imatinib. We describe a case of successful rechallenge of imatinib in a patient with imatinib-induced interstitial pneumonitis and CML without a recurrence of the underlying disease after 3 months of follow-up.

Primary mediastinal choriocarcinoma is an extremely rare extragonadal germ cell malignancy. A 58-year-old male presented with a lung mass, which was incidentally discovered during a periodic medical checkup. Percutaneous needle biopsy showed poorly differentiated carcinoma with large pleomorphic morphology. After the patient underwent right upper lobectomy and lymphadenectomy, the final diagnosis was choriocarcinoma. The patient received four sequential cycles of BEP chemotherapy (bleomycin, etoposide, cisplatin). After completion of BEP chemotherapy, follow-up positron emission tomography (PET) showed a complete metabolic response. Although the mediastinum is one of the most common primary sites of extragonadal germ cell tumors, primary mediastinal choriocarcinoma is liable to be misdiagnosed as lung cancer or Hodgkin lymphoma. Notably, large cell carcinoma of the lung can be confused with choriocarcinoma even after percutaneous needle biopsy. We report a case of primary mediastinal choriocarcinoma mimicking large cell carcinoma of the lung in a male patient in his 50s.