An incredibly diverse list of subspecialties exists in Pathology. Many areas have fellowships or specific training available. Those for which board-certification is available are indicated by an *. Subspecialties in Anatomic Pathology areas are listed first, followed by Clinical Pathology, and lastly, some that are independent. Pathology is unique in that in academic Pathology the structure of the field allows motivated practitioners to become even more specialized according to areas of interest and expertise.

Anatomic Specialties

Cytopathology*
Cytopathology is the area of Anatomic Pathology focusing on cell morphology (the physical form of the cell) for diagnoses. The Cytopathologist is responsible for diagnosing such diverse specimens as gynelogical pap smears and fine needle aspirations ( FNA's ). It requires a fellowship year for board certification. Flow cytometry, which is used to classify cells on the basis of surface markers, is a subset of cytopathology.

Dermatopathology*
Dermatopathology is essentially the Surgical Pathology of the skin. Two years of fellowship are required for certification, one of which is clinical experience. The fellowships are open to Dermatology residents as well. Biopsies and resection margins form the bulk of the work.

Forensic Pathology*
Probably the best publicly known branch of pathology, Forensic Pathology deals with the medicolegal aspects of criminology and death. The bulk of the time is spent doing autopsies whose aim is focused on determining the cause of death. Scene investigation, testifying in court, and toxicology are all utilized to produce an objective flow of medical information into the judicial system. It is quite separate from other branches of pathology due to jurisdictional legal considerations.

Neuropathology*
Of two years in length, neuropathology fellowships involve experience with nerve and brain biopsies, as well as consultations from the autopsy service for CNS lesions. There is a strong research predilection in this subspecialty.

Pediatric Pathology*
The Pediatric pathologist specializes in the gamut of diseases of gestation and childhood. Much correlation with both autopsy and surgical services is required.

Surgical Pathology
Surgical Pathology is the dissection and inspection of surgical specimens in order to inform the Surgeon of specific information vital to the patient's welfare. This includes assessing the margins of a tumor and examining biopsy specimens. The specimens are usually processed by either the methodical "grossing in" (dissection and submission of areas for histological slide preparation) and "signing out" of slides on the next day, or the more rapid "frozen section" (where tissue is quickly frozen in liquid nitrogen, cut into thin slices, stained, and interpreted immediately). In these cases a result is needed to proceed with the surgery and these require close communication with the surgery. Though many subspecialties of surgical pathology exist, in academic centers many Pathologists function as general Surgical Pathologists. Although one year Fellowships exist, no board certification is available.

Renal Pathology
Renal Pathologists are experts in diagnosis of complex diseases of the kidney. Biopsy specimens form the bulk of the work and are one area in which with electron microscopy is required. Renal pathologists are often involved with kidney transplant services to asses rejection. In general one year of training is available without board certification.

Cardiovascular Pathology
A research heavy subspecialty, Cardiovascular Pathology entails transplant service work, myocardial biopsy examination, valve examination, and involvement with the autopsy service. Training is not formalized, and is often done in conjunction with a research fellowship. It is sometimes combined with Pulmonary Pathology or Cardiopulmonary Pathology.

Pulmonary Pathology
Like Cardiovascular Pathology: this is a fellowship that is research oriented with an emphasis on transplant service work as well as surgical pathology autopsy consults. Training is usually one semester with no board certification available.

Gastrointestinal Pathology
This fellowship involves surgical biopsies primarily interpreting from the GI tract. Close consultation with Gastroenterologists is required. Typically a one year fellowship without board certification.

Gynecologic Pathology
The area of Surgical Pathology focusing on the female reproductive tract. There is much focus on tumor Pathology, and often Breast Pathology is considered its own subspecialty. This is a high research area.

Genitourinary Pathology, Musculoskeletal Pathology, Hepatopathology
Extremely specialized branches of Pathology with a large focus on tumors, mostly sarcomas. Jobs exist in big centers only.

Clinical Specialties

Blood Banking / Transfusion Medicine*
Blood Banking / Transfusion Medicine is the branch of clinical Pathology concerned with the scientific basis of transfusion, selection and recruitment of blood donors, utilization, quality control, and preparation of blood components, pretransfusion testing, transfusion of components, adverse reactions, auto immunity, histocompatibility, therapeutic aphoresis and phlebotomy, blood substitutes, medicolegal considerations of transfusion, paternity analysis, management aspects of blood services, and the history of blood transfusion. Training is one year in length, and is a very management oriented.

Chemical Pathology*
The Chemical Pathologist is the manager of the chemical laboratory and oversees development, operation and quality control. These specialist must be experts in the clinical interpretation of lab results, as they consult with physicians on their significance on a daily basis. The fellowship is one year in duration.

Hematopathology*
A one year fellowship program prepares residents for specialization in diagnosis of hematopoetic tissues. A high degree of patient contact is required in coagulation consultations and performance bone marrow biopsies. Close working relationships with Hematology / Oncology specialists are necessary.

Medical Microbiology*
Medical Microbiology is the specialty dealing with the detection and differentiation of infections agents(bacterial, viral, fungal and parasitic). The specialty incorporates much of the expanding field of molecular diagnostics (utilized for molecular diagnostic probes) and has several research oriented subspecialties. As in other Clinical Pathology subspecialties, the one year program is focused not only in acquiring diagnostic acumen but also in laboratory management.

Molecular Diagnostics
A relatively new and expanding branch of Pathology utilizing the science of molecular biology for diagnostics. It presently has applications in Microbiology, Cancer Pathology, and research. At present, ad hoc arrangements are the most common training method.

Pathology Informatics
Another new and expanding subspecialty of Pathology, it is a branch of the more general field of Medical Informatics that is concerned with the study of how medical information is derived and used, including medical statistics, decision making, and all aspects of medical computing. Pathology Informatics focuses upon the use of medical information by, and derived from, the practice of pathology. Most frequently, this includes clinical laboratory systems, tele-pathology (remote consultation via the transfer of diagnostic images, data, and other medical information over computer networks), database design, and mathematical modeling for research purposes. Currently under emphasized due to a general lack of expertise and understanding, it is gaining ground. Training is generally by ad hoc arrangement.

Toxicology
Toxicology deals with the testing for manufactured chemicals in the blood. Through therapeutic drug monitoring, assessment of illicit drug use and for medical legal purposes.