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Indiana Association 
of Pathologists, Inc.
Histology Laboratory, Indiana Medical History Museum 
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March 2018

An 81 year-old man with preauricular squamous cell carcinoma and an incidental lesion in the left parotid gland


Natalia Rush, MD

Fellow in liver and gastrointestinal pathology 

Indiana University School of Medicine



    

Don-John Summerlin, DMD

Adjunct Professor of Pathology & Laboratory Medicine






Jiehao Zhou, MD, PhD

Assistant Professor of Pathology & Laboratory Medicine




Clinical history

The patient is an 81 year-old man who presented for excision of biopsy-proven preauricular squamous cells carcinoma with lymph node dissection and left superficial parotidectomy. A clinical history of hypertension and hypothyroidism was documented. Preoperative imaging revealed enlarged regional lymph nodes that were suspicious for metastatic disease and an atrophic parotid gland. On gross examination, an incidental lesion was identified in the parotidectomy specimen.

Gross description

On sectioning, an ill-defined, rubbery-to-firm, white-tan nodule was identified. This lesion was located in the central aspect of the parotidectomy specimen measuring 1.9 x 1.2 x 1.3 cm.

Microscopic description

Microscopic examination revealed multifocal periductal lymphoid infiltrates composed of small- to medium-size lymphocytes with monocytoid appearance (Figure 1 and 2). The infiltrate appeared to destroy the acinar tissue and infiltrate the ducts, forming lymphoepithelial lesions with epimyoepithelial islands.


Figure 1. Periductal and periacinar lymphocytic infiltrate with associated acinar atrophy, H&E.



Figure 2. High-power view of periductal lymphocytic collar. Note lymphocytes appear small with monocytoid and plasmacytoid morphology.


Ancillary studies

An initial immunohistochemistry panel revealed that the lymphocytic infiltrates were predominantly  B cells (CD20 positive) that co-express CD43 (Figure 3). Additional immunohistochemistry showed that the tumor cells were positive for BCL-2 (strong diffuse) but negative for CD10, CD5, BCL6 (not shown), Cyclin D1 (not shown) and CD23 (not shown) excluding the possibility of follicular lymphoma, mantle cell lymphoma and small lymphocytic lymphoma (Figure 4). CD138, kappa, lambda, showed polyclonal plasma cells (not shown).



Figure 3. Initial immunohistochemical panel demonstrated marked predominance of CD20 positive lymphocytes with CD43 coexpression and only scattered CD3 positive T cells.


Figure 4. An additional immunohistochemical panel revealed lack of CD10 and CD5  expression and positivity for BCL-2 while BCL6, cyclin D1 and CD23 were negative (not shown).


Immunoglobulin heavy chain (IgH) gene rearrangement PCR analysis identified clonal PCR product for all three primer sets FR1-JH (325 bp), 

FR2-JH (264 bp) and FR3-JH (126 bp) (Figure 5). 



Figure 5. PCR Immunoglobulin heavy chain (IgH) gene rearrangement analysis

 March 2018-Final Diagnosis and Discussion



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