—  SPECIALTY CONFERENCE  —

Dermatopathology

Case 8 - Subcutaneous Panniculitis-like T-cell Lymphoma

Sabine Kohler
Stanford University
Palo Alto, CA


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Definition:
A tumor of alpha/beta CD8+ cytotoxic T-cells with almost exclusive involvement of the subcutaneous tissues. Cell size ranges from small, to medium-sized or large.

Clinical
This lymphoma affects a wide age range. Patients develop subcutaneous nodules most frequently on legs, trunk, arms, face. Initially this disease follows an indolent course, but some patients develop a usually fatal hemophagocytic syndrome, manifesting as pancytopenia and/or coagulopathy. Sometimes subcutaneous nodules are accompanied by fever and malaise. Hepatosplenomegaly can be present but lymphadenopathy is usually absent.

Histology
Lobular panniculitis that appears deceptively benign. Polymorphous infiltrate centered on fat with rimming of fat cells by atypical cells. Karyorrhexis results in so-called bean bag cells. Many cases show angioinvasion/ angiodestruction and are associated with fat necrosis. Hemophagocytosis may be present.


Case 8 - Figure 1 - Subcutaneous nodule on lower extremity.
Case 8 - Figure 2 - Lobular lymphoid infiltrate.
Case 8 - Figure 3 - For the most part the subcutaneous infiltrate is mixed. Few areas contain a monomorphous population.



Case 8 - Figure 4 - A focally angiocentric growth pattern is present.
Case 8 - Figure 5 - Rimming of fat cells by atypical lymphocytes.



Case 8 - Figure 6 - "Bean bag cells". Macrophages with phagocytosed debris.
Case 8 - Figure 7 - Mixed lobular infiltrate with pronounced angiocentricity.


A histiocytic/ granulomatous component is usually present and may be the predominating feature. +/- dermal involvement.

Immunophenotype
CD8+, (sometimes coexpression of CD8+ and CD4+), CD4-, TIA-1+, CD3+, CD56-. BF1+

Genetics/molecular
Cloncally rearranged T-cell receptor, but no specific chromosomal abnormalities. EBV negative.

Prognosis
Protracted clinical course, often with spontaneous temporary remissions. Some patients develop a terminal hemophagocytic syndrome after prolonged disease duration.

Differential Diagnosis
lupus panniculitis, cytophagic histiocytic panniculitis

Comment
Initial description of SPLTL included cases with a gamma/delta T-cell phenotype. These cases are often CD4-, and CD8- double negative and co-express CD56. These cases pursue an aggressive clinical course and are excluded from the SPLTL category in the WHO-EORTC. They are grouped either with extranodal NK/T cell lymphoma, nasal type or gamma/delta T-cell lymphoma.

References

  1. Subcutaneous panniculitic T-cell lymphoma is a tumor of cytotoxic T lymphocytes. Hum Pathol. 1998 Apr;29(4):397-403.

  2. Marzano AV, Berti E, Paulli M, Caputo R. Cytophagic histiocytic panniculitis and subcutaneous panniculitis-like T-cell lymphoma: report of 7 cases. Arch Dermatol. 2000 Jul;136(7):889-96.

  3. Salhany KE, Macon WR, Choi JK, Elenitsas R, Lessin SR, Felgar RE, Wilson DM, Przybylski GK, Lister J, Wasik MA, Swerdlow SH. Subcutaneous panniculitis-like T-cell lymphoma: clinicopathologic, immunophenotypic, and genotypic analysis of alpha/beta and gamma/delta subtypes. Am J Surg Pathol. 1998 Jul;22(7):881-93.

  4. Massone C, Chott A, Metze D, Kerl K, Citarella L, Vale E, Kerl H, Cerroni L. Subcutaneous, blastic natural killer (NK), NK/T-cell and other cytotoxic lymphomas of the skin. Am J Surg Pathol 2004;28:719-735.

  5. El Shabrawi-Caelen L, Cerroni L, Kerl H. The clinicopathologic spectrum of cytotoxic lymphomas of the skin. Semin Cutan Med Surg 2000 Jun;19(2):118-123.

  6. Santucci M et al. Cytotoxic/ Natural killer cell cutaneous lymphomas. Cancer 2003,97:610-627.