Surgical pathology •Examined all tissues and foreign objects removed from living patients •Specimens not to be submitted must be written as hospital policy •Practice of pathologists •Pathological diagnosis : “ Gold standard in medicine ”
Specimen collection in surgical pathology •Incisional biopsy : for diagnostic purpose •Excisional biopsy : for diagnostic and therapeutic purposes •Tissue collection by instruments : needle biopsy, core biopsy, punch biopsy, curettage, shave biopsy, Bard biopsy, endoscopic biopsy •Necropsy = biopsy from dead body •Organs from operation rooms
General rules for the biopsy • •Larger the lesion - more numerous biopsies • •Ulcerated tumor – recommend peripheral biopsy • •Avoid necrosis and hemorrhage areas • •All fragments must be sent to the pathology department • •Not crushing, squeezing, cautery • •Immediately fix in fixatives • •Orientating specimen e.g. deep margin, superior and inferior margins by using sutured threads (long, short)
Fixation of the tissue •Hard tissues take more time to thoroughly fixed than soft tissue. •Penetration rate, around 1 mm./hr. in general (variable, depends on consistency of the tissue). •10 times volume of fixative over the specimen volume is needed.
Fixatives Neutral buffered formalin - fixation time hours. •Formalin (40% aqueous solution of formaldehyde) - 100ml •Sodium dihydrogen orthophosphate (monohydrate) - 4g •Disodium hydrogen orthophosphate (anhydrous) - 6.5g •Distilled water - 900ml This fixative is suitable for most histological purposes. It is to be preferred to formol-saline (a single 10% solution of formalin in 9% aqueous NaCl) as formalin pigment is avoided. Specimens may be stored in this fluid. The solution is isotonic.
Filling the request forms (1) 1. identified of the patient 2. identified specimen ( gross appearance, cyst, vascular, inking for margin) type of surgery ( biopsy, wide excision) surgical finding 3. adequate clinical history (necessary) prior diagnosis, immune status (HIV), prior treatment : radiation, chemotherapy bone lesion : X-ray finding
Filling the request forms (2) bone lesion : X-ray finding hematolgic disease : CBC, bone marrow female reproductive lesion : LMP, hormone hepatitis : LFT 4. Clinical diagnosis or differential diagnosis
Immunohistochemistry and HER2 study •Use formalin-fixed paraffin embedded tissue (paraffin block) •Must have request forms
Frozen section •Intraoperative consultation •Fresh tissue was immediately freezed in liquid nitrogen and make an ultrathin section in cryostat •Frozen section is not a permanent section
Cryostat •Cryostat = microtome in the freezing cabinet.
Indications for frozen section •Benign or malignant lesions •Adequacy of surgical margins •Metastatic lymph node : sentinel nodes in breast carcinoma •Presence or absence of ganglion cells in large intestinal wall of Hirschsprung disease
Diagnosis of frozen section •Benign VS malignant : not specific diagnosis •In case of doubt – wait for permanent section
Specimens for frozen section •Fresh tissue –< 1cm. in size is recommended. •Put in plastic bag, tightly closed with rubber bands •Label on the plastic bag •Place the plastic bag in ice •Send it to pathology lab immediately
Inappropriate specimens for frozen section •Large tumor or specimens •Highly infectious specimens : TB, HIV •Follicular lesion of thyroid (can not diffentiate between benign and malignant)
Cytopathology •The study of individual cells or small clusters of cells for diagnosis and screening of diseases, including cancers • practice of screeners, cytotechnicians, cytopathologists
Cytogenetics •Study structure of chromosome from cell culture •FISH in chromosome of leukemia •Specimens –Whole blood –Bone marrow –Amniotic fluid
Specimen collection for cytogenetics •Sterile techniques •2-5 ml. of blood or bone marrow in heparinized tube or sterile heparinized syringe •20 ml. of amniotic fluid in sterile disposable syringe •Send to lab immidiately (with request form) or keep in refrigerator not more than 12 hours
Service hours for cytogenetics •For blood specimen : Mon, Tue, Fri •For Bone marrow : Mon, Thur •For amniotic fluid : Tue •Blood and bone marrow for FISH : Mon-Fri