CD30-Negative Cutaneous T-Cell Lymphomas Other than Mycosis Fungoides

Molecular pathogenesis of Cutaneous T cell Lymphoma: Role of chemokines, cytokines, and dysregulated signaling pathways

Cutaneous T cell lymphomas (CTCLs) are a heterogeneous group of lymphoproliferative neoplasms that exhibit a wide spectrum of immune-phenotypical, clinical, and histopathological features. The biology of CTCL is complex and remains elusive. In recent years, the application of next-generation sequencing (NGS) has evolved our understanding of the pathogenetic mechanisms, including genetic aberrations and epigenetic abnormalities that shape the mutational landscape of CTCL and represent one of the important pro-tumorigenic principles in CTCL initiation and progression. Still, identification of the major pathophysiological pathways including genetic and epigenetic components that mediate malignant clonal T cell expansion has not been achieved. This is of prime importance given the role of malignant T cell clones in fostering T helper 2 (Th2)-bias tumor microenvironment and fueling progressive immune dysregulation and tumor cell growth in CTCL patients, manifested by the secretion of Th2-associated cytokines and chemokines. Alterations in malignant cytokine and chemokine expression patterns orchestrate the inflammatory milieu and influence the migration dynamics of malignant clonal T cells. Here, we highlight recent insights about the molecular mechanisms of CTCL pathogenesis, emphasizing the role of cytokines, chemokines, and associated downstream signaling networks in driving immune defects, malignant transformation, and disease progression. In-depth characterization of the CTCL immunophenotype and tumoral microenvironment offers a facile opportunity to expand the therapeutic armamentarium of CTCL, an intractable malignant skin disease with poor prognosis and in dire need of curative treatment approaches.

[Facial ulcerated nodules revealing primary cutaneous CD8-positive aggressive epidermotropic cytotoxic T-cell lymphoma]

BACKGROUND

Primary cutaneous CD8+ aggressive, epidermotropic, cytotoxic T-cell lymphoma is a rare disease with a poor prognosis. Herein we report a new case, with facial lesions, which was difficult to diagnose.

PATIENTS AND METHODS

A 39-year-old woman was hospitalized for ulcerated nodules on the face that had been developing rapidly for 8 weeks. She had visited Djerba, Tunisia, 3 months earlier. No abnormalities were found on previous routine blood tests. Histopathological analysis of a skin biopsy had revealed non-specific lymphocytic infiltrate. Various therapies, including amoxicillin/clavulanic acid, valaciclovir, corticosteroids, colchicine and doxycycline, proved ineffective. Screening of the cutaneous sample for leishmaniasis proved positive using PCR but negative by direct examination and culture. Treatment was initiated with meglumine antimoniate. A further cutaneous biopsy revealed diffuse lymphocytic proliferation and led to a diagnosis of cutaneous CD8+ aggressive, epidermotropic, cytotoxic T-cell lymphoma. A PET scan showed multiple sites of hypermetabolism affecting the face and lymph nodes. Meglumine antimoniate was stopped and the patient experienced complete remission after chemotherapy.

CONCLUSION

Ulcerated nodules with acute progression on acral sites are characteristic of cutaneous CD8+ aggressive, epidermotropic, cytotoxic T-cell lymphoma. In our case, the positive result of PCR screening for Leishmania that was ultimately considered a false positive was a confounding factor in the diagnostic process. Regarding therapy, aggressive treatment strategies such as multiagent chemotherapy and hematopoietic stem-cell transplantation are needed due to the rapid progression of the lymphoma.

Cardiac Involvement and Subsequent Death due to Extranodal NK/T Cell Cutaneous T-Cell Lymphoma: An Autopsy Case and Brief Review of the Literature

Cardiac tumors range from benign to high grade malignancies. The incidence of cardiac involvement either by primary, or secondary tumors during autopsy is reported to be extremely low. Extranodal NK/T-cell lymphoma (ENKTL), nasal type is an unusual type of lymphoma. The skin is the second most common site of involvement after the respiratory tract. We present a case of a 63-year-old male, who was recently diagnosed with ENKTL, nasal type, who received chemotherapy, and died without any evident cause. The corpse was referred for routine medicolegal examination. Macroscopical determination of the cause of death was not feasible and subsequent histopathological examination revealed heart infiltration by ENKTL that was found in vivo in cutaneous lesions. Similar infiltrations existed in the pancreatic tissue. To the best of our knowledge, myocardial infiltration of ENKTL, inducing severe myocardial lesions that eventually caused death, is rare, with limited cases reported in the literature.

Activated-cytotoxic TCRαβ+CD4+ peripheral T-cell lymphoma with hypodermal localization: Case report of a lymphoproliferative disorder probably evolved from the CD4+ cytotoxic T-cell subpopulation

The World Health Organization (WHO) classification of hematopoietic and lymphoid tumors identifies distinctive subtypes of peripheral T-cell lymphoma (PTCL), and, additionally, some PTCLs involving mostly extranodal sites like the skin. The difficulty of classifying PTCLs according to the normal stages of T-cell differentiation and the lack of definitive diagnostic markers for most of the subtypes make the diagnosis of these diseases challenging. PTCL cases which do not fit into any of the specifically defined entities are categorized as PTCL not otherwise specified (PTCL-NOS). PTCLs-NOS represent less than 2% of the total cases of T-cell lymphoma involving the skin. This article illustrates a case of a PTCL-NOS in which tumor cells have an activated cytotoxic TCRαβ+CD3+CD4+CD56+ T-cell phenotype and histopathologic features of subcutaneous panniculitis-like T-cell lymphoma, leading to a fatal outcome.

Cutaneous Metastases: A Review and Diagnostic Approach to Tumors of Unknown Origin

CONTEXT.—

Cutaneous metastases from a distant malignancy are a diagnostic challenge for pathologists. Secondary involvement of the skin by a metastatic process portends a much worse clinical prognosis than any primary cutaneous malignant mimickers. Immunohistochemical staining methods continue to evolve and are of paramount importance in diagnosis.

OBJECTIVE.—

To review the clinical, histopathologic, and immunohistochemical staining patterns for commonly encountered entities and discuss potential pitfalls in diagnosis. A practical guide useful in approaching cutaneous metastases of unknown primary is outlined.

DATA SOURCES.—

An extensive search and review of literature in PubMed was performed, processed, and condensed.

CONCLUSIONS.—

Cutaneous metastases have broad histopathologic patterns. They are nearly always dermal based, with an overall foreign appearance. They can be single papules/nodules or multiple in number, mimicking an inflammatory or infectious process. Ultimately, immunohistochemistry remains an essential diagnostic tool, and clinical correlation is paramount in the workup of these entities.

NK/T-cell lymphoma, nasal type, γδ T-cell lymphoma, and CD8-positive epidermotropic T-cell lymphoma-clinical and histopathologic features, differential diagnosis, and treatment

The cytotoxic lymphomas of the skin constitute a heterogeneous group of rare lymphoproliferative diseases that are derived from mature T cells and natural killer (NK) cells that express cytotoxic molecules (T-cell intracellular antigen- 1, granzyme A/B, and perforin). Although frequently characterized by an aggressive course and poor prognosis, these diseases can have variable clinical behavior. This review delivers up-to-date information about the clinical presentation, histopathologic features, differential diagnosis, and therapy of extranodal NK/T-cell lymphoma, nasal type, primary cutaneous gamma delta T-cell lymphoma, and primary cutaneous CD8+ aggressive epidermotropic cytotoxic T-cell lymphoma.