Lymph Nodes, Axillary: Diagnosis



Lymph Nodes, Axillary: Diagnosis










Afferent lymphatics enter the node in a central plane. Bisecting the node in this plane is most likely to reveal metastasis. Macrometastases should be detectable regardless of the plane of section.






Metastatic carcinoma usually forms a firm white mass that replaces the normal brown to red nodal tissue. Smaller metastases, or diffusely infiltrative metastases, may not be grossly visible.


SURGICAL/CLINICAL CONSIDERATIONS


Goal of Consultation



  • Determine if macrometastatic (≥ 2 mm) carcinoma is present in sentinel lymph node(s)



    • Metastases < 2 mm may or may not be detected


Change in Patient Management



  • If metastasis is present, additional lymph nodes may be excised



    • If no additional surgery is planned, there is no need for intraoperative evaluation of lymph nodes


Clinical Setting



  • In the past, decisions concerning systemic therapy for breast cancer relied heavily on nodal status



    • Systemic therapy vs. no systemic therapy


    • Chemotherapy vs. hormonal therapy alone


  • Currently, molecular type of breast cancer is more commonly used for these decisions



    • Well- or moderately differentiated estrogen receptorpositive cancers with a low proliferative rate are generally treated with hormone therapy alone


    • Poorly differentiated estrogen receptor-negative or HER2-positive cancers are generally treated with chemotherapy


  • Nodal status is predictive of survival but not response to therapy; therefore, nodal sampling may not be necessary in some patients


  • Some patient groups as defined by the ACOG Z0011 trial may not undergo axillary dissection if only 1 or 2 sentinel nodes are positive


SPECIMEN EVALUATION


Gross



  • All nodes are carefully bluntly dissected from specimen and counted



    • Number of nodes present and with metastases are used to determine need for additional surgery


  • If there is a gradient of blue dye, metastasis is most likely to be at the blue-stained pole


  • Each node is thinly sliced at 2 mm intervals


  • All slices of all nodes are frozen



    • If there is a grossly evident metastasis, only 1 representative section need be frozen



      • Scrape or touch preparation can also be used to document grossly positive lymph node


    • If node is grossly suspicious for lymphoma or granulomatous disease, preservation of nonfrozen tissue is helpful for ancillary studies



      • Flow cytometry, frozen tissue (molecular studies), and hematopathology fixatives for suspected lymphoma


      • Cultures for granulomatous disease


  • If each node is inked a different color, slices from > 1 node can be frozen in same block



    • It is important to be able to count number of nodes with metastasis


  • Radioactive nodes detected with usual techniques employed do not expose pathology personnel to dangerous levels of radiation



    • Special protective equipment is not required


    • Special storage or disposal of tissue or equipment are not necessary


    • If new or nonstandard technique is utilized, levels of radiation and resulting risk should be assessed


    • Handling procedures should be approved by institutional radiation safety office


Frozen Section



  • All slices of all nodes are frozen



    • At least 1 H&E slide including a complete cross section of all slices is evaluated


Cytology



  • Each cut surface is scraped with a curved scalpel blade or glass slide and smeared on another slide


  • Each node should be separately evaluated


  • Useful when either infection or lymphoma are suspected



    • Touch imprints, rather than scrape preparations, may be more helpful for lymphoma



RT-PCR



  • This technique has been proposed as an alternative to frozen section evaluation


  • Does not clearly distinguish metastases by size


  • False-negative results can occur



    • Some cases due to failure of carcinoma to express transcripts used for assay


  • False-positive results can occur



    • Transcription of mRNA from nontumor cells can occur



      • Contamination of specimens by nonmalignant epithelial cells is a concern


    • If large portions of tissue are taken (e.g., using 1/2 a node for assay), macrometastases may not be seen by histology


    • It may be impossible to distinguish a false-positive from a true-positive



      • Clinical significance of cases with positive RT-PCR result and negative result by histology is unclear


      • Node could have no tumor cells, isolated tumor cells, micrometastasis, or missed macrometastasis


REPORTING


Frozen Section



  • Presence or absence of metastases


  • Extranodal invasion, if present


  • Presence or absence of other pathologic processes


  • Number of positive and negative nodes


  • Size of lymph node metastases


Cytology



  • Number of positive nodes with estimated gross size of metastasis, number of negative nodes


MOST COMMON DIAGNOSES


Metastatic Breast Carcinoma



  • Most common carcinoma found in axillary nodes of women


  • If a blue dye gradient is present, metastasis is usually present at blue pole


  • Ductal and lobular carcinoma are most common variants



    • Metastatic tumor often resembles primary



      • Preoperative review of slides or reports can be very helpful for correlation


      • If metastatic tumor and primary are dissimilar, consider alternative diagnoses (e.g., benign inclusions or metastases from other sites)


    • Metastatic grade I and II lobular carcinomas can be very difficult to identify in nodes


  • Metastases may be focal



    • Usually present adjacent to peripheral subcapsular sinus


    • Rare metastases are present in center of node


  • Metastases (particularly from lobular carcinoma) may resemble reactive processes


Lymphoma



  • Would be an unusual and unexpected finding in axillary nodes of a woman with breast cancer



    • Women with known low-grade lymphoma/chronic lymphocytic leukemia may have nodal involvement


  • Cytologic preparations are helpful to reveal morphology and dyscohesive nature of cells


  • If sufficient tissue is available, tissue should be saved for special studies



    • Frozen tissue (DNA analysis)


    • Flow cytometry


    • Fixatives for hematopathology



      • If Hodgkin lymphoma or diagnoses other than lymphoma are possible, tissue should also be fixed in formalin


Melanoma



  • Tumor cells usually appear dyscohesive with markedly pleomorphic nuclei


  • Tumors that are pigmented grossly or microscopically are easy to identify



    • However, many metastatic melanomas do not exhibit obvious melanin production


  • Patients usually have well-known history of melanoma



    • In rare cases, metastatic melanoma to breast can be mistaken for a primary breast carcinoma


Sarcoidosis



  • Rarely involves axillary lymph nodes


  • Node is occupied by confluent noncaseating granulomas


  • Infection should be excluded by sending tissue for culture


Benign Inclusions



  • Usually look like well-formed tubules



    • Myoepithelial cells may be present


    • Breast stroma may or may not be present


    • May show apocrine or squamous metaplasia


    • Endosalpingiosis is present as single-layered tubules



      • Cells may be ciliated


  • Prior biopsies of benign or malignant papillary lesions can result in dispersal of papillary fragments in lymphatic and lymph nodes



    • Usually present as small cohesive clusters


  • Immunoperoxidase studies may be required for final classification


Silicone



  • Can seep out of implants (“bleed”) or be released when implant is ruptured


  • Can be transferred to regional lymph nodes


  • Silicone granulomas can be very hard and gritty when cut



    • Gross appearance and texture can closely mimic metastatic carcinoma


  • Silicone fills histiocytes


  • Silicone and metastatic carcinoma can be present in same lymph node


PITFALLS


False-Negative Diagnoses

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Jul 7, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Lymph Nodes, Axillary: Diagnosis

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