Assessment of diagnostic criteria between primary cutaneous anaplastic large-cell lymphoma and CD30-rich transformed mycosis fungoides; a study of 66 cases.

BACKGROUND: Transformed mycosis fungoides (TMF) large cells may express CD30 antigen, and because of this, the differential diagnosis between CD30-rich TMF and primary cutaneous anaplastic large-cell lymphoma (cALCL) may be difficult, and especially in distinguishing cALCL associated with MF vs. CD30-rich TMF. OBJECTIVES: To find clinical, histological and molecular diagnostic features useful for differential diagnosis between cALCL and CD30-rich TMF. To analyse and compare the prognostic value of clinical and pathological factors in these two diseases. MATERIAL AND METHODS: We conducted a retrospective study (1999-2012) of 32 patients with cALCL and 34 with CD30-rich TMF, seen in reference centres of the French Study Group of Cutaneous Lymphoma. Clinical, histological and molecular features were analysed and compared to determine their diagnostic and prognostic value. RESULTS: Comparison of the two groups showed that age ˃ 60 years, ≥ 5 skin lesions, early progression, absence of spontaneous regression and trunk involvement were significantly associated with the diagnosis of TMF. Abnormal T-cell phenotype and perforin expression were significantly more frequent in cALCL (both P < 0·001). Overall survival (OS) at 5 years was 77·4% for cALCL and 20·7% for CD30-rich TMF. Stage T3, ≥ 5 skin lesions, lower limb involvement for cALCL and stage T4, extracutaneous involvement, B symptoms, high levels of lactate dehydrogenase for CD30-rich TMF were associated with poor OS and progression-free survival. DUSP22 gene rearrangement had no diagnostic or prognostic value. CONCLUSIONS: Clinical features and outcome are the most discriminative to differentiate the two entities. Even histological and molecular markers were not fully specific; abnormal vs. normal T-cell phenotype and perforin expression may constitute helpful tools.

Two congenital cases of pigmented epithelioid melanocytoma studied by fluorescent in situ hybridization for melanocytic tumors: case reports and review of these recent topics.

The term 'pigmented epithelioid melanocytoma' (PEM) has recently been proposed as a nosological framework grouping lesions formerly known as animal-type melanomas, sporadic epithelioid blue nevi and Carney complex-associated epithelioid blue nevi. Congenital PEMs have been reported extremely rarely and their prognosis is poorly known. Four-color fluorescent in situ hybridization (FISH) for melanocytic lesions is a recent method developed to assess the malignant potential of ambiguous melanocytic lesions. Here we describe 2 cases of congenital epithelioid and strongly pigmented melanocytic lesions consistent with PEM. No BRAF gene mutation was found in the 2 cases. FISH for melanocytic lesions was also performed. The first case proved entirely negative, whereas the second one showed a positive zone with an extra copy of chromosome 6. The prognosis and management of PEM are discussed, with a review of the available data on the history, demographics, molecular alterations and histopathological aspects of this entity. PEM seems to represent a unique low-grade melanocytic tumor with a limited potential of metastasis to lymph nodes, but a favorable long-term clinical course. The published data about FISH for melanocytic tumors, and especially PEM, are reviewed. Four-color FISH may be a useful tool to assess more accurately the prognosis of these tumors.