18F-FDG PET/CT in Lymphomatoid Papulosis Mimicking Primary Cutaneous Anaplastic Large Cell Lymphoma.

Lymphomatoid papulosis is a benign self-healing condition, presenting as papulonodular skin eruptions and mimicking malignant cutaneous lymphomas histopathologically. F-FDG PET/CT findings in this benign condition have not been described in detail in the literature. We present a case of lymphomatoid papulosis mimicking primary cutaneous anaplastic large cell lymphoma histopathologically and demonstrating intensely FDG-avid cutaneous lesions on F-FDG PET/CT, which disappear spontaneously in the follow-up scan.

Dermoscopy of Lymphomas and Pseudolymphomas.

Primary cutaneous lymphomas are a heterogeneous group that includes 2 main groups of primary T- and B-cell lymphomas, which can involve the skin with distinct variability in clinical presentation, histopathology, immunophenotypes, molecular signature, and prognosis. The authors describe the most frequent clinical forms of cutaneous lymphomas and their dermoscopic features. Even if the diagnosis of these entities is still based on a cellular level and the literature on dermoscopy in cutaneous lymphomas is limited and, for several entities it is based only on single case reports/case series, we think that know how they appear also in dermoscopy can be useful for helping in the clinical diagnosis.

A rare case of ALK negative CD30+ primary cutaneous anaplastic large cell lymphoma in a young adult.

Cutaneous anaplastic large cell lymphoma can present either as a primary disease or as secondary to a pre-existing systemic anaplastic lymphoma. Distinguishing primary cutaneous anaplastic lymphoma (PC-ALCL) from its systemic counterpart requires a complete clinical and laboratory workup. We hereby report a case of PC-ALCL in a young adult, who presented with unusual rapidly progressive ulcerated mass in the neck. Biopsy showed anaplastic large cells, which were strongly positive for CD30 and CD25 but ALK1 gene product was negative. Clinical examination and computed tomography (CT) scan ruled out extracutaneous involvement. Chemotherapy with 6 cycles of CHOP regimen was planned and on follow-up, a complete remission of the lesion was attained.

FDG-PET in T-cell and NK-cell neoplasms.

BACKGROUND: A growing number of studies demonstrate the utility of (18)fluoro-2-deoxyglucose positron emission tomography (FDG-PET) in the management of malignant lymphoma. The results of FDG-PET, however, have not been studied extensively for T-cell and natural killer (NK)-cell neoplasms. PATIENTS AND METHODS: We retrospectively evaluated pretreatment FDG-PET scans in 41 patients with T/NK-cell neoplasms diagnosed according to the World Health Organization (WHO) classification. Histological subtypes frequently included were peripheral T-cell lymphoma, unspecified (PTCLu, n = 11), extranodal NK/T-cell lymphoma, nasal type (ENKL, n = 8), primary cutaneous anaplastic large cell lymphoma (C-ALCL, n = 5), and angioimmunoblastic T-cell lymphoma (AILT, n = 4). RESULTS: FDG-PET detected a lymphoma lesion in at least one site in 36 out of 41 patients. The positive rate was equally high in most histological subtypes except for cutaneous lymphomas: PTCLu 91%, ENKL 100%, C-ALCL 60%, AILT 100%. All the patients without an FDG-avid lesion had lesions restricted to skin. Among patients who had cutaneous lesions, only 50% had FDG-avid cutaneous lesions, all of which were tumorous. The positive rate of FDG-PET for bone marrow involvement was only 20%. CONCLUSION: T/NK-cell neoplasms incorporated in this study were generally FDG-avid except for cutaneous lesions and bone marrow involvement.