Cytologically Yours: CoW: 20140206

Clinical Summary

The patient is a 12 year old female with a six month history of left shoulder pain. The patient had tried Aleve and had several chiropractic visits which were unsuccessful at relieving the pain.

Past Medical History

• Previously heathy

Past Surgical History

• No surgical history

Radiology

• AP/Lateral images show a destructive and aggressive appearing lesion in the left proximal huerus in the metaphysis extending 7.5cm distally in the diaphysis.

Clinical Plan

The differential diagnosis included osteosarcoma and Ewing sarcoma. MRI and CT guided biopsy are scheduled.

Pathology

Cytology

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  40x magnification of highly atypical malignant appearing cells.

• CytologicallyYoursCoW201402062Cytology2.jpg

  20x magnification showing osteoid formation.

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  40x magnification showing osteoid formation and malignant appearing cells.

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  40x magnification of osteoid.

Resident Questions

• What is your differential diagnosis?

These groups of cells demonstrate malignant appearing cells in a background of an otherwise benign appearing lymphoid background. The atypical cells are scattered, with large nucleoli and several binucleate forms. In addition, there seem to be an increased number of eosinophils in the background. The differential diagnosis includes Hodgkin lymphoma; however, the possibility of the large atypical cells being melanoma cannot be ruled out.

• What ancillary tests would you recommend?

For this patient, we recommended that the radiologist perform a biopsy of the lesion so that it could be sent for immunohistochemical workup. Since the overall percentage of the atypical cells were low, we were worried that a cell block would not contain enough of the malignant cells for additional stains. We also sent the lymph node for flow since a hematologic malignancy was suspected; however, with Hodgkin lymphoma, we don't expect any diagnostic findings from flow cytometry.

• What immunohistochemical stains would you do?

CD15, CD30, and PAX5 would stain tumor cells in Hodkin lymphoma. Mart1, HMB45, and S100 could be used to rule out melanoma. Other additional stain in a lymphoma versus melanoma workup might include CD3, CD20, and keratin.

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Final Diagnosis

Cytology

• Positive for malignancy, the differential diagnosis includes melanoma and Hodgkin lymphoma.

Biopsy

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  20x magnification of lymph node core biopsy.

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  40x magnification of lymph node core biopsy.

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  CD 15 with membranous staining.

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  CD 30 with membranous staining.

Biopsy Diagnosis

• Classical Hodgkin lymphoma, favor mixed type.
  • CD15 Positive in tumor cells
  • CD30 Positive in tumor cells
  • PAX5 Weakly positive
  • CD20 Positive in background lymphocytes
  • CD3 Positive in background lymphocytes
  • S100 Negative
  • Mart1 Negative
  • HMB45 Negative

Discussion

The features of Hodgkin lymphoma include atypical (Hodgkin cells) and Reed-Sternberg cells. The nucleus should be 3-4x the size of a small lymphocyte. In classic Hodgkin lymphoma, scattered eosinophils, plasma cells, histiocytes, and a predominately CD3+ lymphocyte population will be seen in the background. The immunophenotype of classic Hodgkin lymphoma shows CD15, CD30, MUM1, and weak PAX5 positivity. Histology is usually needed to subtype Hodgkin lymphoma.