Overview
Surgical pathology includes the gross and microscopic examination of resected specimens and biopsies by histopathologists for tissue diagnosis. Several precise steps must be followed to prepare tissue in a form that can be examined under the light microscope and yield a reliable diagnosis.
This foundational lesson introduces the entire workflow โ from receipt of surgical specimens through to dispatch of reports โ and covers the critical roles of grossing, gross room design, histopathology laboratory equipment, and laboratory safety.
Learning Objectives
- List the steps involved in processing surgical specimens for histopathological examination
- Explain the after-care of specimens after diagnosis is made
- Define grossing and describe the functions of the gross room
- List the essential equipment and features of a gross room
- Describe the equipment present in the histopathology laboratory
- Identify the key laboratory hazards and apply appropriate safety measures
Clinical Story
A surgeon removes a suspicious lump from a patient's breast during an operation. That specimen arrives in the histopathology laboratory in a container of formalin. Before the pathologist can ever look down a microscope, the laboratory technician must receive, label, gross, process, embed, section, and stain that tissue correctly. One error at any step can lead to a wrong diagnosis. This lesson teaches you those steps.
Steps in Processing Surgical Specimens
Specimens arrive from the operating theatre (OT) in appropriate fixative containers with completed request forms including patient identity and clinical details.
Macroscopic examination of the specimen with the naked eye. The pathologist describes size, shape, colour, consistency, and selects representative sections for microscopy.
Selected tissue blocks are dehydrated, cleared, and infiltrated with paraffin wax using an automated tissue processor.
Processed tissue blocks are embedded in molten paraffin wax and oriented correctly in moulds to form solid paraffin blocks.
A microtome cuts sections of 3โ5 micrometres thickness from the paraffin block. These are floated on warm water and mounted on glass slides.
Sections are stained (typically H&E), coverslipped, and labelled with patient and specimen details.
Completed slides are dispatched to the pathologist for microscopic examination and diagnosis.
After-Care of Specimens & Records
Once the diagnosis is made and reports dispatched to surgeons, the laboratory must perform the following:
| Item | Storage Period | Purpose |
|---|---|---|
| Glass slides | Minimum 10 years | Future reference, teaching, research |
| Requisition forms | Minimum 10 years | Medicolegal, audit, reference |
| Well-preserved specimens | Long-term | Teaching, research, museum |
| Reference specimens | 6 months โ 1 year | Future clinical reference |
| Unwanted specimens | Discard after use | Not useful for any of the above |
Depending on resources and requirements, a surgical pathology laboratory may also perform: Cryosections, Histochemical stains, Immunohistochemistry, Electron microscopy, and advanced techniques such as in-situ hybridisation and immunofluorescence.
Grossing
Grossing is the process by which pathology specimens are inspected with the naked eye (macroscopic examination) to obtain diagnostic information before microscopic processing.
Points to Note Before Processing
Confirm the patient identity and the anatomical site from which the specimen was obtained. Cross-check with the request form before any processing begins.
All relevant clinical history, including the surgeon's findings, suspected diagnosis, and any prior pathology, must be reviewed before grossing.
A written record of the physical appearance of the specimen โ size (measured), shape, colour, consistency, surface characteristics, and any lesions identified. Only a small representative portion of a large specimen goes for microscopy, so gross examination must be performed by a skilled person.
โข Only soft tissue can be cut directly into small blocks
โข Bony specimens must be decalcified before processing
โข Stones and teeth require special treatment before sectioning
Gross Room Design & Equipment
The gross room is the dedicated space where macroscopic examination and dissection of specimens takes place.
Design Requirements
The room must be large enough for all pathologists to work simultaneously. It must be well illuminated and well ventilated with an exhaust fan to remove formalin vapours.
Essential Equipment
Additional Items (Best Practice)
Histopathology Laboratory Equipment
The histopathology laboratory must be large enough to accommodate all equipment and personnel comfortably. Core equipment includes:
Laboratory Hazards & Safety Measures
Formalin vapours are irritant to eyes and throat. Always use an exhaust fan as an outlet for vapours. Never work in a closed gross room without ventilation.
Always wear mask, apron, eye glasses and gloves to protect against: infected material, formalin vapours, and spilt blood or body fluids.
- Keep the grossing table clean with antiseptic solution at all times
- All specimens must be in containers with 10% formalin and covered with a lid
- After grossing, specimens must be stored according to their accession number
Many chemicals in the histopathology lab are inflammable โ wax, xylene, alcohol, acetone. Store these at a separate designated location. Minimum quantities should be kept in the laboratory. A fire extinguisher must always be available.
Most equipment runs 24 hours, 7 days a week. Check all electrical connections before leaving the laboratory every day.
Some chemicals are carcinogenic or harmful to skin. Always wear gloves for staining and all chemical-handling procedures.
Interactive Quiz
5 QuestionsFlashcards
Tap to flipCase Study
A surgical specimen labelled "Right mastectomy" arrives in the histopathology lab. The container is sealed with 10% formalin. The accompanying request form shows patient name, age, and clinical note: "Suspicious mass, right breast, FNAC showed malignant cells." The specimen is given accession number HP-2025-0437.
- โEvery specimen must have a unique accession number before any processing begins
- โClinical details guide which blocks to sample during grossing
- โThe entire 7-step process must be completed correctly before diagnosis is possible
Quick Revision
10-Minute ReviewKey Takeaways
- Surgical pathology includes gross and microscopic examination of resected specimens and biopsies for tissue diagnosis
- The 7 steps are: receipt, grossing, tissue processing, embedding, section cutting, staining, and dispatch
- Slides and requisition forms must be stored for at least 10 years
- Grossing is macroscopic inspection of specimens with the naked eye to obtain diagnostic information
- The gross room must be large, well illuminated, well ventilated with exhaust fan, and stocked with all essential instruments
- All specimens must be stored in 10% formalin in covered containers
- PPE โ gloves, mask, apron, eye glasses โ must be worn in the gross room at all times
- Inflammable chemicals must be stored separately; a fire extinguisher must always be available in the histopathology laboratory