Solitary Small- to Medium-Sized Pleomorphic T-Cell Nodules of Undetermined Significance: Clinical, Histopathological, Immunohistochemical and Molecular Analysis of 26 Cases

Abstract

Background: Solitary skin nodules composed of pleomorphic T lymphocytes are often the source of diagnostic problems. Objective: To characterize the clinicopathological features, prognosis and optimal treatment modalities of patients with solitary lymphoid nodules of small- to medium-sized pleomorphic T lymphocytes. Methods: Twenty-six patients were analysed for clinical, histopathological, immunophenotypical, molecular and follow-up data. Results: Lesions were located mainly on the head and neck (n = 16; 61.5%) or trunk (n = 8; 30.8%). Histopathology showed non-epidermotropic nodular or diffuse infiltrates of small- to medium-sized pleomorphic T lymphocytes. Monoclonality was found by PCR in 54.2% of cases (n = 13/24). After a mean follow-up of 79.7 months, a local recurrence could be observed only in 1 patient. Conclusions: Our patients have a specific cutaneous lymphoproliferative disorder characterized by reproducible clinicopathological features. The incongruity between the indolent clinical course and the worrying histopathological features poses difficulties in classifying these cases unambiguously as benign or malignant. We suggest to describe these lesions as ‘solitary small- to medium-sized pleomorphic T-cell nodules of undetermined significance’. Irrespective of the name given to these equivocal cutaneous lymphoid proliferations, follow-up data support a non-aggressive therapeutic strategy.

A Case of Primary Cutaneous CD4 Positive Small/medium T Cell Lymphoma

“…In our case, the age at the onset of the skin lesion was 63 years and she presented with multiple, multifocal lesions. Multifocal lesions similar to our case have been less commonly described [11][12][13][14] .…”

“…Histologically, PCSM-TCL is characterized by a dense infiltration of small/medium sized pleomorphic T cells 9,[11][12][13][14] . Clonal T cell receptor gene rearrangement has been detected in most cases.…”

“…Immunohistochemically, CD3 and CD4 are positive, but CD8 and CD30 are negative in the majority of the case, and sometimes this is combined with the loss of the pan T cell markers 1,5,[11][12][13][14] . However, many studies have also reported tumors that are CD8 positive or CD4 negative 1,5,9,11,12 . In addition, many PCSM-TCL cases have shown a rich infiltrate of reactive B cells 14 .…”

Controversies and Considerations in the Diagnosis of Primary Cutaneous CD4+ Small/Medium T-Cell Lymphoma

“…7,8 Although it affects individuals with a wide age range, including children, 10,12,15À18 most patients are older adults with an average age in the 50s to 60s and without a clear sex predilection. 3,4,7,10,12,[15][16][17][18][19][20][21] Patients typically present with a solitary, asymptomatic lesion on the face, neck, upper trunk, or upper extremities, which may appear as a violaceous papule, plaque, nodule, or tumor. * Some early series, before PC-SMTCL was a well-defined entity, reported a relatively high frequency (50%-74%) of multiple lesions in a localized or generalized distribution.…”

“…Frequently, the infiltrate extends into the subcutaneous fibroadipose tissue, and it may also involve skeletal muscle, vessels, and adnexal structures, sometimes with invasion and destruction of vessels and adnexae. 4,6,7,10,[15][16][17][18][19][20][21][22]26 Lymphoid cells are most often separated from the epidermis by a grenz zone, but focal epidermotropism may be seen. 3,4,7,8,19,20,22 Notably, prominent epidermotropism should prompt consideration of a diagnosis of MF.…”