VANCOUVER, B.C. — A biopsy from the scalp of this 88-year-old patient revealed a deep and diffuse lymphoid infiltrate extending into fat.
The histopathology of this lesion resembled a follicle from a lymph node, and it contained a germinal center, a mantle zone, and a surrounding marginal zone.
“Of note, there was a grenz zone, a sparing of the papillary dermis, which is characteristic of B-cell lymphoma,” commented Jenny Murase, M.D., a dermatology resident at the University of California, Irvine, who presented the case at the annual meeting of the Pacific Dermatologic Association.
Immunohistochemical stains were performed, with CD20 and CD79 marking nodular aggregates. “These are present in malignant B cells,” she said.
CD3, CD7, and CD43 marked smaller background lymphocytes, which are T-cell markers.
Also relevant was positive CD- 30 (Ki-1) staining, consistent with a diagnosis of follicular B-cell lymphoma, recently renamed follicle center cell lymphoma by the World Health Organization.
“Interestingly, CD10 staining was negative, although it is usually positive in follicle center lymphoma,” Dr. Murase said.
The patient's positive BCL-2 gene findings helped to clinch the diagnosis.
Dr. Murase explained several features that can aid in differentiating progressive transformation of germinal centers from lymphoma.
“Germinal centers have significant mitoses as compared to neoplasms,” she said. In addition, tingible body macrophages contain “ingested nuclear debris, which represents lymphocytes that have been selected to be destroyed in reactive follicles.
“This selection process will not occur in neoplasms,” she said.
Follicular B-cell lymphoma, or follicle center cell lymphoma, represents about 30% of cases of non-Hodgkin's lymphoma. Its incidence has been rising by 3%–5% per year for 20 years.
The median age at diagnosis is 60–65 years.
An indolent clinical course is common. Median survival is 5–10 years, and the survival rate is 75%.
“This tumor is very radiosensitive,” Dr. Murase said.
Recent studies have suggested that rituximab (Rituxan) and fludarabine (Fludara) have a greater chemotherapeutic effect on this cancer than commonly used multidrug combinations.
Dr. Murase's patient had a normal blood chemistry panel and CT scan. However, a PET scan revealed activity in the lower left anterior cervical region and bilateral pulmonary hila involvement. A bone marrow biopsy showed extensive disease, and the patient was staged as IVA.
He received a 6-week course of 375 mg of infused rituximab which he tolerated well and which led to a resolution of his pruritus. He remains alive with his disease.
Dr. Murase said the case demonstrates the need to biopsy and work up a patient who is not responding to traditional therapy for a seemingly simple problem.
Moreover, “I feel this case demonstrates that very subtle skin findings can have potentially serious implications. In this case, a patient's pruritic scalp led us to his bone marrow involvement,” she said.