Leptomeningeal cancer (also called  leptomeningeal carcinomatosis, leptomeningeal disease (LMD), leptomeningeal metastasis, neoplastic meningitis, meningeal metastasis and meningeal carcinomatosis) is a rare complication of cancer in which the disease spreads from the original tumor site to the meninges surrounding the brain and spinal cord. This leads to an inflammatory response, hence the alternative names neoplastic meningitis (NM), malignant meningitis, or carcinomatous meningitis. The term leptomeningeal (from the Greek lepto, meaning fine or slight) describes the thin meninges, the arachnoid and the pia mater, between which the cerebrospinal fluid is located. The disorder was originally reported by Eberth in 1870.It occurs with cancers that are most likely to spread to the central nervous system. The most common cancers to include the leptomeninges are breast cancer, lung cancer, and melanomas because they can metastasize to the subarachnoid space in the brain which offers a hospitable environment for the growth of metastatic tumor cells. Individuals whose cancer has spread to an area of the brain known as the posterior fossa have a greater risk of developing a leptomeningeal cancer. The condition can also arise from primary brain tumor like medulloblastoma. Leptomeningeal disease is becoming more evident because cancer patients are living longer and many chemotherapies cannot reach sufficient concentrations in the spinal fluid to kill the tumor cells. Signs and symptoms
The most common symptoms of leptomeningeal cancer is pain and seizures. The other symptoms may include headaches (usually associated with nausea, vomiting, light-headedness), gait difficulties from weakness or ataxia, memory problems, incontinence, sensory abnormalities.
Proximal femoral focal deficiency (PFFD), also known as Congenital Femoral Deficiency (CFD),   is a rare, non-hereditary birth defect that affects the pelvis, particularly the hip bone, and the proximal femur. The disorder may affect one side or both, with the hip being deformed and the leg shortened. It is commonly linked with the absence or shortening of a leg bone (fibular hemimelia) and the absence of a kneecap. Other linked birth defects include the dislocation or instability of the joint between the femur and the kneecap, a shortened tibia or fibula, and foot deformities. Causes
The cause of PFFD is uncertain. Two hypotheses have been advanced. The theory of sclerotome subtraction posits injury to neural crest cells that are the precursors to sensory nerves at the level of L4 and L5. Histologic studies of a fetus with unilateral PFFD have prompted an alternative hypothesis that PFFD is caused by a defect in maturation of chondrocytes (cartilage cells) at the growth plate. In either hypothesis, the agent causing the injury is usually not known. Thalidomide is known to cause PFFD when the mother is exposed to it in the fifth or sixth week of pregnancy, and it is speculated that exposure to other toxins during pregnancy may also be a cause. Other etiologies that have been suggested, but not proven, include anoxia, ischemia, radiation, infection, hormones, and mechanical force. PFFD occurs sporadically, and does not appear to be hereditary.