What the Pathologist Needs

What the Pathologist Needs

Prepared by Dr. llkay TOSUN

Accurate pathological diagnosis is the cornerstone of musculoskeletal tumor management. Even the most advanced imaging cannot replace high-quality, representative tissue and precise clinical context. The pathologist’s ability to deliver an accurate diagnosis depends not only on tissue quality but also on the quality of information provided by the surgeon. Effective communication between the surgical, radiologic, and pathology teams is therefore essential.

Essential Clinical Information

When submitting a biopsy or resection specimen, the following details must be clearly documented on the pathology request form and discussed, ideally in a multidisciplinary setting:

• Patient demographics: Age, sex, and relevant medical history (especially prior malignancy or radiation).
• Clinical presentation: Duration of symptoms, pain, swelling, growth rate, trauma history.
• Anatomical location: Specific bone, side (right/left), and compartment (intramedullary, cortical, soft-tissue).
• Radiologic findings: Summary of MRI, CT, and X-ray features (matrix pattern, cortical involvement, soft-tissue extension).
• Suspected diagnosis or differential diagnosis: To guide appropriate sampling and staining.
• Previous procedures: Any prior biopsy, curettage, or surgery must be mentioned, as they may alter histologic appearance.

Tissue Handling and Labelling

• Mark orientation: Use sutures or ink to identify margins and anatomical orientation.
• Avoid crush or cautery artifact: Handle tissue gently to preserve architecture.
• Separate samples: If both soft-tissue and bone are present, send them in separate containers.
• Include imaging correlation: Providing printed or digital images helps the pathologist select representative areas for sectioning.

Communication During Intraoperative Consultation

In frozen-section or intraoperative evaluation, the pathologist must be informed of:

• The surgical goal (diagnosis confirmation vs. margin assessment).
• The area of interest (solid vs. necrotic, viable vs. cystic).
• Whether margin evaluation is required, and from which site.
  Surgeons should ensure timely specimen delivery to prevent desiccation or thermal artifact.
• The pathologist’s main intraoperative contribution is to confirm tissue adequacy and margin status, rather than to provide an immediate tumor type.
• Accurate diagnosis relies on a combination of clinical, radiologic, and histologic data — emphasizing the importance of multidisciplinary tumor board discussions.

Frozen Section Limitations

Frozen section (intraoperative consultation) is not suitable for diagnosing bone and soft-tissue tumors.

• Soft-tissue tumors are inherently heterogeneous, and frozen sections may not reflect the entire lesion.
• Bone tumors require decalcification for accurate evaluation, which is a time-dependent process and cannot be performed during frozen examination.
• Therefore, definitive diagnosis should not be expected from frozen sections in musculoskeletal oncology.

However, frozen sections may be useful for assessing surgical margins, especially in wide resections or recurrent cases.

Sampling and Biopsy Considerations

• Small or limited biopsies (e.g., tru-cut or core biopsies) may not always provide a definitive diagnosis because large tumors are often heterogeneous.
• Extensive sampling is essential — ideally at least one tissue block per centimetre of tumor diameter — to capture representative areas, including viable, necrotic, and atypical regions.
• Close coordination between the surgeon and pathologist ensures correct orientation, adequate fixation, and avoidance of crush artefacts.

Common Challenges

• Non-representative sampling: Necrotic or hemorrhagic areas yield non-diagnostic results.
• Lack of clinical context: Leads to misclassification (e.g., distinguishing infection from neoplasm).
• Improper fixation: Inadequate formalin volume (should be 10× tissue volume) affects morphology.
• Delayed transport: Causes autolysis and RNA degradation, limiting molecular studies.

Key Points

• The pathologist needs context as much as tissue — imaging findings, clinical suspicion, and surgical notes are indispensable.
• Always coordinate with pathology before biopsy for specimen handling and ancillary test planning.
• Representative, well-oriented, and fresh tissue improves diagnostic accuracy.
• Successful diagnosis in MSK oncology is a team process, not a laboratory event.

References

1. Mankin HJ, Hornicek FJ. Diagnosis, Classification, and Management of Bone Tumors: The Importance of Multidisciplinary Communication. J Am Acad Orthop Surg. 2017;25(8):540–551.
2. Bridge JA, et al. Molecular Diagnostics of Bone and Soft Tissue Tumors: Evolving Role in Classification and Therapeutics. Mod Pathol. 2020;33(S1):27–44.
3. O’Donnell P, Tirabosco R, Saifuddin A. What the Pathologist Needs from the Radiologist in Bone Tumour Diagnosis. Skeletal Radiol. 2018;47(10):1321–1332.
4. Fletcher CDM, et al. WHO Classification of Soft Tissue and Bone Tumours, 5th Edition. IARC Press, 2020.