Pathologists often encounter soft tissue neoplasms while examining biopsies and excisions from the skin. Soft tissue neoplasms are classified along their line of differentiation and include fibroblastic, myofibroblastic and fibrohistiocytic tumors, smooth muscle tumors, skeletal muscle tumors, neural tumors, lipomatous tumors, vascular tumors, pericytic and perivascular tumors and tumors of uncertain differentiation. These tumors can be categorized as benign, intermediate (locally recurrent/aggressive), intermediate (rarely metastasizing) and malignant (locally recurrent/aggressive with significant metastatic potential). Histologic diagnosis, grading and staging is imperative for prognostication and treatment. The continually expanding array of molecular diagnostics techniques has identified numerous novel gene alterations in soft tissue neoplasms that has enabled identification of new diagnostic entities with accompanying diagnostic and surrogate immunohistochemical markers. In this chapter we will review many soft tissue neoplasms and highlight important immunohistochemical markers.

Artifacts are EEG waveforms not generated by the brain. The main purpose of recognizing artifacts is to avoid mistaking them from seizures. They may originate from other body organs (internal) or environmental sources (external). Common internal artifacts include ocular (eye movement), glossokinetic (tongue movement), cardiac (ECG), myogenic (muscle activity), or sweat-sway artifact (skin). Common sources of external artifact include electrodes, ventilators, suction devices, bed percussion, chest compression, and various medical devices. Many commonly used medications are associated with EEG changes. These include excessive alpha and beta activity (e.g., barbiturates and benzodiazepines), theta and delta slowing (antiseizure and psychotropic medications), spike and sharp waves (clozapine), and rhythmic and/or periodic patterns (cefepime). EEG patterns of common intravenous and inhalational anesthetic agents are also described in this chapter.