Historically, adenocarcinoma was more often seen peripherally in the lungs than SCLC and squamous-cell lung cancer, both of which tended to be more often centrally located. Recent studies, though, suggest that the "ratio of centrally to peripherally occurring" lesions may be converging toward unity for both adenocarcinoma and squamous-cell carcinoma. Squamous-cell lung carcinoma
Squamous-cell carcinoma (SCC) of the lung is more common in men than in women. It is closely correlated with a history of tobacco smoking, more so than most other types of lung cancer. According to the Nurses Health Study, the relative risk of SCC is around 5.5, both among those with a previous duration of smoking of 1 to 20 years, and those with 20 to 30 years, compared to "never smokers" (lifelong nonsmokers). The relative risk increases to about 16 with a previous smoking duration of 30 to 40 years, and roughly 22 with more than 40 years. Large-cell lung carcinoma
Large-cell lung carcinoma (LCLC) is a heterogeneous group of undifferentiated malignant neoplasms originating from transformed epithelial cells in the lung. LCLCs have typically comprised around 10% of all NSCLC in the past, although newer diagnostic techniques seem to be reducing the incidence of diagnosis of "classic" LCLC in favor of more poorly differentiated SCCs and adenocarcinomas. LCLC is, in effect, a "diagnosis of exclusion", in that the tumor cells lack light microscopic characteristics that would classify the neoplasm as a small-cell carcinoma, squamous-cell carcinoma, adenocarcinoma, or other more specific histologic type of lung cancer.
Bacteria
Lyme disease
Syphilis
Leptospirosis
Fungi
Cryptococcal infection
Coccidioidal infection
Drug-induced aseptic meningitis (DIAM)
Irritation of the meninges from drugs administered directly to the spinal canal or subarachnoid space. The hypersensitivity to the drug results in an immune response. Autoimmune diseases
Systemic lupus erythematosus. Cancer-caused aseptic meningitis such as neoplastic meningitis
This affects about 5% of all cancer cases, with a predominance in leukemias. Neurosarcoidosis

Diagnosis
The term aseptic can be misleading, implying a lack of infection. On the contrary, many cases of aseptic meningitis represent infection with viruses or mycobacteria that cannot be detected with routine methods. Medical professionals will take into consideration the season of the year, the medical history of the individual and family, physical examination, and laboratory results when diagnosing aseptic meningitis.One common medical test used when diagnosing aseptic meningitis is lumbar puncture. A medical professional inserts a needle between two vertebrae to remove cerebrospinal fluid (CSF) from the spinal cord. The cerebrospinal fluid collected from the lumbar puncture is analyzed by microscope examination or by culture to distinguish between bacterial and aseptic meningitis. Samples of CSF undergo cell count, Gram stains, and viral cultures, and polymerase chain reaction (PCR). Polymerase chain reaction has increased the ability of clinicians to detect viruses such as enterovirus, cytomegalovirus, and herpes virus in the CSF, but many viruses can still escape detection. Other laboratory tests include blood, urine, and stool collection. Medical professionals also have the option of performing a computed tomographic (CT) scan or magnetic resonance imaging (MRI), these tests help observe calcifications or abscesses.