Three children with CD30 cutaneous anaplastic large cell lymphomas bearing the t(2;5)(p23;q35) translocation

Anaplastic Lymphoma Kinase in Cutaneous Malignancies

Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase that has been implicated in the pathogenesis of a variety of neoplasms. As suggested by its name, ALK was first described as part of a translocation product in cases of anaplastic large-cell lymphoma, with other genetic and cytogenetic ALK mutations subsequently coming to attention in the development of many other hematologic and solid organ malignancies. ALK has now been shown to play a role in the pathogenesis of several cutaneous malignancies, including secondary cutaneous systemic anaplastic large-cell lymphoma (ALCL) and primary cutaneous ALCL, melanoma, spitzoid tumors, epithelioid fibrous histiocytoma, Merkel cell carcinoma, and basal cell carcinoma. The characterization of ALK-positivity in these cutaneous malignancies presents exciting opportunities for utilizing ALK-targeted inhibitors in the treatment of these diseases.

Pediatric case of anaplastic lymphoma kinase-positive anaplastic large cell lymphoma forming a solitary skin tumor on the forearm

A 5-year-old girl noticed a rapidly growing reddish nodule on her right forearm. Although oral antibiotics had been administrated for 2 weeks, the tumor enlarged. Skin biopsy revealed excessive infiltration of atypical neoplastic cells expressing CD4, CD30 and anaplastic lymphoma kinase (ALK). These histological and immunohistochemical findings were consistent with anaplastic large cell lymphoma (ALCL). Computed tomography showed multiple lymphadenopathy, but lymph node biopsy and bone marrow examination did not show any evidence of systemic dissemination. However, due to the positive results for ALK and multiple lymphadenopathy, we diagnosed ALK-positive ALCL forming a solitary skin tumor on the forearm. The patient received chemotherapy and presented marked improvement. This paper discusses the difficulty of diagnosing pediatric ALK-positive ALCL limited to the skin and reviews the medical published work.

Paediatric cutaneous lymphomas: a review and comparison with adult counterparts

Primary cutaneous lymphomas (CL) in children is rare. Only a few studies focused specifically on paediatric CL and therefore little is known whether primary CL in children are similar to or different from their adult counterparts with respect to the clinicopathological presentation, behaviour and prognosis. An extensive literature search using PubMed/MEDLINE from January 1995 through July 2014 was undertaken for articles reporting cases of paediatric CL. In addition, we identified 31 children with CL in our institutions. Mycosis fungoides and lymphomatoid papulosis are the two most prevalent lymphoma forms in children. A few entities of cutaneous lymphomas such as cutaneous diffuse large B-cell lymphoma leg type, and Sézary syndrome have not been reported so far in children. Other lymphoma entities such as hydroa vacciniforme-like lymphoma are mostly seen in certain geographic areas (Asia, Central and South America). In the paediatric population, low-malignant indolent forms such as primary cutaneous marginal zone lymphoma and primary cutaneous follicle centre lymphoma are very rare, whereas the more aggressive forms of B-cell lymphomas, precursor lymphoblastic lymphomas, and blastic plasmacytoid dendritic cell neoplasm are the most common forms in children, mostly involving the skin secondarily. Most paediatric lymphomas have similar clinicopathological features and course as their adults counterparts, particularly in the group of cutaneous T-cell lymphomas. The spectrum of cutaneous B-cell lymphomas in children significantly differs from the one in adults. Diagnostic work-up and treatment of paediatric patients with lymphomas are best achieved in close collaboration with paediatric haematopathologists and oncologists.

ALK-positive (2p23 rearranged) anaplastic large cell lymphoma with localization to the skin in a pediatric patient

Anaplastic large cell lymphoma (ALCL) either as primary cutaneous or nodal disease is rare in children and difficult to distinguish, which is important both prognostically and for treatment purposes. We present a case of anaplastic lymphoma kinase (ALK)+ skin-limited ALCL that highlights this challenge and draws attention to pitfalls in assessing ALK status. The patient was an 11-year old girl with a twice recurrent nodule on her right shoulder. Each biopsy revealed a deep infiltrate of atypical lymphocytes that expressed CD3, CD4, CD43, CD45RO and CD30. The initial biopsy was epithelial membrane antigen (EMA)+ with vague cytoplasmic ALK-1 positivity by immunohistochemistry, while the second biopsy was EMA+ and nuclear ALK-1+. Fluorescence in situ hybridization analysis for an ALK (2p23) rearrangement of the first specimen was negative, while an ALK gene rearrangement was present in the second specimen. Therefore, this case was treated as nodal ALCL, despite negative bone marrow and radiographic imaging studies. The patient was treated with combination chemotherapy and remains disease-free. Demonstration of nuclear ALK-positivity, ALK (2p23) gene rearrangement is suggestive of systemic ALCL. Without evidence of systemic disease, this case highlights challenges of skin-limited ALCL, whose clinical behavior as either cutaneous ALCL systemic ALCL may not be immediately apparent.

Gene deregulation and spatial genome reorganization near breakpoints prior to formation of translocations in anaplastic large cell lymphoma

Although the identification and characterization of translocations have rapidly increased, little is known about the mechanisms of how translocations occur in vivo. We used anaplastic large cell lymphoma (ALCL) with and without the characteristic t(2;5)(p23;q35) translocation to study the mechanisms of formation of translocations and of ALCL transformation. We report deregulation of several genes located near the ALCL translocation breakpoint, regardless of whether the tumor contains the t(2;5). The affected genes include the oncogenic transcription factor Fra2 (located on 2p23), the HLH protein Id2 (2p25), and the oncogenic tyrosine kinase CSF1-receptor (5q33.1). Their up-regulation promotes cell survival and repression of T cell-specific gene expression programs that are characteristic for ALCL. The deregulated genes are in spatial proximity within the nuclear space of t(2;5)-negative ALCL cells, facilitating their translocation on induction of double-strand breaks. These data suggest that deregulation of breakpoint-proximal genes occurs before the formation of translocations, and that aberrant transcriptional activity of genomic regions is linked to their propensity to undergo chromosomal translocations. Also, our data demonstrate that deregulation of breakpoint-proximal genes has a key role in ALCL.

Primary cutaneous CD30+ anaplastic large cell lymphoma: report of a rare case

Primary cutaneous anaplastic large cell lymphoma (PCALCL) is a rare type of non-Hodgkin's lymphoma comprising approximately 0.9-9.0% of all cutaneous lymphomas. PCALCL is characterized by the absence of systemic involvement, spontaneous regression and low recurrence rate especially in localized lesions.We present a 47-year-old female with a 1½-year history of two asymptomatic erythematous indurated plaques on the right arm. Skin punch biopsy revealed dense infiltrates of non-epidermotropic, large, irregularly-shaped lymphocytes with hyperchromatic and pyknotic nuclei. Immunohistochemistry revealed that these atypical cells are anaplastic lymphoma kinase (ALK) positive, CD30+, CD3-, CD20- and epithelial membrane antigen (EMA) negative. Clinical, histopathological and immunohistochemical findings are consistent with PCALCL. Work-ups revealed no systemic involvement. Short course CHOP (Cyclophosphamide, Doxorubicin, Vincristine, and Prednisone) chemotherapy resulted in total resolution of skin lesions; however, recurrence was noted 12 months after treatment. She then underwent radiotherapy and achieved complete remission.Because the clinical presentation of PCALCL can be variable, a high index of suspicion is necessary in patients presenting with chronic plaques and nodules unresponsive to topical or oral medications.

The morphologic spectrum of primary cutaneous anaplastic large T-cell lymphoma: a histopathologic study on 66 biopsy specimens from 47 patients with report of rare variants

BACKGROUND

Primary cutaneous anaplastic large T-cell lymphoma (PCALCL) is a well-defined entity with prognostic differences from the nodal counterpart [nodal anaplastic large cell lymphoma (NALCL)]. Several histological variants of NALCL have been characterized (common, lymphohistiocytic and small cell). However, studies on morphological variants of PCALCLs are lacking.

METHODS

We analyzed retrospectively the clinicopathologic features of 66 biopsies from 47 patients (M : F = 27 : 20; median age: 53 years; mean age: 51.8 years; range: 14-82) with PCALCL, in order to better characterize the spectrum of this unusual neoplasm.

RESULTS

The 'common variant' was the most frequent (40.4%). In contrast to NALCL, in PCALCL, marked reactive infiltrates are more commonly present. In fact, 26 cases were classified as 'inflammatory type' (15 cases) and 'lymphohistiocytic' (11 cases). Concerning the predominant cell morphology, large anaplastic cells (33%) were almost as frequent as large pleomorphic (36%) and small to medium-sized cells (26%). We reported for the first time in the skin 2 rare cases with the predominance of large cells with a 'signet-ring'-like appearance. Epidermotropism and presence of eosinophils were found in a proportion of cases in all PCALCL variants.

CONCLUSIONS

PCALCL is characterized by variable histopathological presentations and a broad cytomorphologic spectrum.

Lymphoproliferative lesions of the skin

Diagnosis and differential diagnosis of cutaneous lymphoproliferative disorders is one of the most difficult areas in dermatopathology, and biopsies are often taken to rule out a cutaneous lymphoma in patients with "unclear" or "therapy-resistant" skin lesions. Histopathological features alone often enable a given case to be classified to a diagnostic group (eg, epidermotropic lymphomas), but seldom allow a definitive diagnosis to be made. Performing several biopsies from morphologically different lesions is suggested, especially in patients with suspicion of mycosis fungoides. Immunohistochemistry is often crucial for proper classification of the cases, but in some instances is not helpful (eg, early lesions of mycosis fungoides). Although molecular techniques provide new, powerful tools for diagnosing cutaneous lymphoproliferative disorders, results of molecular methods should always be interpreted with the clinicopathological features, keeping in mind the possibility of false positivity and false negativity. In many cases, a definitive diagnosis can be made only on careful correlation of the clinical with the histopathological, immunophenotypical and molecular features.