Interactive Case Study - September 2026

17-month-old male with multiple subcutaneous nodules and pancytopenia

Angela M. B. Collie, MD, PhD Senior Associate Consultant

Kathryn E. Yunk Undergraduate Student

A 17-month-old previously healthy male presented with a three-month history of fluctuating, firm, nontender subcutaneous nodules as well as splenomegaly and low-grade fevers. Laboratory analysis revealed pancytopenia, hypertriglyceridemia, hypofibrinogenemia, and elevated ferritin. A punch biopsy of the left lower back was performed.

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Figure 1. H&E

Figure 2. H&E

Figure 3. CD3

Figure 4. CD8

Figure 5. TIA1

Figure 6. TCR-betaF1

Figure 7. TCR-delta

Figure 8. TRBC1 (green) /CD3 (purple) Dual Immunohistochemical Stain

Figure 9. Ki-67

Figure 10. Epstein-Barr virus encoded RNA in situ hybridization (EBER ISH)

Which of the following is the best diagnosis?

Erythema nodosum

Extranodal NK/T-cell lymphoma

Lupus panniculitis

Primary cutaneous gamma-delta lymphoma

Subcutaneous panniculitis-like T-cell lymphoma

What immunohistochemical staining pattern is characteristic for the lymphocytes of subcutaneous panniculitis-like T-cell lymphoma?

CD3-positive, CD4-positive, CD8-negative, TIA-1-positive, TCR-betaF1-positive

CD3-positive, CD4-positive, CD8-negative, TIA-1-positive, TCR-betaF1-negative

CD3-positive, CD4-positive, CD8-positive, TIA-1-positive, TCR-betaF1-positive

CD3-positive, CD4-negative, CD8-positive, TIA-1-positive, TCR-betaF1-positive

CD3-positive, CD4-negative, CD8-positive, TIA-1-positive, TCR-betaF1-negative

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4. Goodlad JR. Updated Classification of Cutaneous Lymphoma. Adv Anat Pathol. 2025;32(3):239-255.
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6. Michonneau D, Petrella T, Ortonne N, et al. Subcutaneous Panniculitis-like T-cell Lymphoma: Immunosuppressive Drugs Induce Better Response than Polychemotherapy. Acta Derm Venereol. 2017;97(3):358-364.
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9. Sonigo G, Battistella M, Beylot-Barry M, et al. HAVCR2 mutations are associated with severe hemophagocytic syndrome in subcutaneous panniculitis-like T-cell lymphoma. Blood. 2020;135(13):1058-1061.
10. Koh J, Jang I, Mun S, et al. Genetic profiles of subcutaneous panniculitis-like T-cell lymphoma and clinicopathological impact of HAVCR2 mutations. Blood Adv. 2021;5(20):3919-3930.
11. Moonla C, Polprasert C, Komvilaisak P, et al. Germline HAVCR2 mutations and their relation to the clinical spectrum of subcutaneous panniculitis-like T-cell lymphoma and hemophagocytic lymphohistiocytosis: results from a multicenter study and meta-analysis. Haematologica. 2023;108(10):2743-2752.
12. Li Z, Lu L, Zhou Z, et al. Recurrent mutations in epigenetic modifiers and the PI3K/AKT/mTOR pathway in subcutaneous panniculitis-like T-cell lymphoma. Br J Haematol. 2018;181(3):406-410.

Acknowledgements

Author Profiles

Angela M. B. Collie, MD, PhD

Mayo Clinic

Angela Collie is a hematopathologist at Mayo Clinic in Rochester, Minnesota. She attended the University of Washington for her M.D. and Ph.D. as a part of the Medical Scientist Training Program before completing AP/CP residency, hematopathology fellowship and dermatopathology fellowship at Cleveland Clinic. With her subspecialty training in both dermatopathology and hematopathology, she has a particular interest in lymphoma and all types of cutaneous hematopoietic disorders.

Kathryn E. Yunk

Denison University

K. Emily Yunk is an undergraduate student at Denison University. She is studying biochemistry on the pre-medicine path. Emily is interested in dermatology and pathology and learning more about both fields.

Question:

Interactive Case Study - September 2026

Acknowledgements

Author Profiles

17-month-old male with multiple subcutaneous nodules and pancytopenia

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