Positron emission tomography: useful in detecting metastatic cancer of unknown primary site.

Metastatic cancer of unknown primary site represents approximately three percent of all new cancer diagnoses. Expensive and invasive diagnostic procedures are often performed although the primary tumour is detected in less than 25 percent of cases. We present a 63-year-old woman presenting with low back pain and was found on positron emission tomography (PET) to have lung cancer. The pros and cons of PET in the diagnostic process of patients with metastatic cancer of unknown primary site are reviewed. PET should be considered in the diagnostic process of patients with unknown primaries, and unnecessary invasive procedures may be avoided.

[Acute transverse myelopathy associated to S. aureus: a difficult differential diagnosis]. / Mielopatía transversa aguda asociada a S. aureus: la dificultad del diagnóstico diferencial.

Acute myelopathy includes a group of diseases with an important associated morbidity, thus early diagnosis and treatment is important. The most frequent etiology is extramedullary compression. Magnetic resonance (MR) is the most suitable procedure in this type of disease since it also offers information on extramedullar lesions and makes it possible to assess spine involvement. We present the case of a 57 year-old man who was admitted because of back pain for several weeks and systemic infection due to S. aureus. Later, he suffered a sudden neurological deficit with spine involvement but without compressive images on the MRI. We discuss the differential diagnosis among intramedullary abscess, epidural abscess, acute transverse myelitis and spondylodiscitis associated to acute myelopathy. We carry out a brief review of the medical literature on diagnosis criteria of those entities.