A Distinct Entity in the Spectrum of the CD30+ Cutaneous Lymphoproliferative Diseases: Oligolesional Nodules With Pseudoepitheliomatous Hyperplasia Followed by Spontaneous Resolution

Critical Review-A Tribute to Louis Brocq Lymphomatoid Papulosis, the Key in Exploring the Relationship of Parapsoriasis and Mycosis Fungoides

ABSTRACT

Both parapsoriasis and LyP appear clinically as inflammatory dermatoses with a paradoxical link to cMF. A key element in addressing the relationship of parapsoriasis and MF were the results of the French and Dutch long-term registries tracking the emergence of lymphomas in the setting of LyP. Both cMF and cALCL emerged almost equally in these long-term studies. This ultimately supports that the stem cells in both cMF and cALCL are probably derived from a common stem cell shared by CD4+/CD8+ memory stem cells defining cMF and CD30+ stem cells defining cALCL. The discovery of inducible Skin Associated Lymphoid Tissue (iSALT) mesenchymal hubs incorporating Tregs, with their pleiotropic functions represents a paradigm shift and formed a translational tool in this analysis of the paradox. LyP can be recast as activated inhibitory lymphomatoid T-cell hubs derived from inducible iTregs in iSALT and the source of the common stem cell LyP line. iSALT Treg integrated mesenchymal hubs provided an emerging translational tool in redefining integrated lymphomatoid pathways. Brocq's complex scheme defining parapsoriasis as hybrid inflammatory dermatoses with a paradoxical link to cMF became a template to preserve parapsoriasis as a clinical diagnosis. Two major iSALT Treg generated inhibitory integrated lymphomatoid hubs emerged. The major CD30+TNF lymphomatoid hub has been linked to cALCL. Clinically defined chronic regressing and relapsing parapsoriasis with the histopathology of patch stage MF can be redefined as lymphomatoid parapsoriasis. This twin inhibited oncogenic memory based hub is defined by Treg modulated, CD4+/CD8+memory linked PD-1/DL-1 cytoxic complex and lichenoid histopathology.

Pseudocarcinomatous Hyperplasia Masquerading as a Well-Differentiated Squamous Cell Carcinoma Associated With Primary Cutaneous Anaplastic Large-Cell Lymphoma

ABSTRACT

Pseudocarcinomatous hyperplasia (PCH) is a reactive proliferation of the epidermis associated with CD30 + lymphoproliferative disorders. In this article, we report the case of a 42-year-old man who presented with a 10-year history of a solitary erythematous patch on the right thigh that progressed to an ulcerated, crusted plaque. Histologic examination revealed an infiltrate of atypical CD30 + lymphocytes consistent with primary cutaneous anaplastic large-cell lymphoma with overlying well differentiated keratinocyte hyperplasia akin to a well-differentiated invasive squamous cell carcinoma. This case demonstrates the phenomenon of pseudocarcinomatous hyperplasia mimicking features of invasive squamous cell carcinoma. It highlights the necessity of careful clinical correlation when diagnosing squamous cell carcinomas in younger patients on non-sun-exposed areas and the exclusion of accompanying known causes of pseudocarcinomatous hyperplasia.

Pseudocarcinomatous Hyperplasia, Squamous Cell Carcinoma, and Keratoacanthoma Associated to Lymphomas of the Skin and External Mucous Membranes: A Case Report and Literature Review

Pseudocarcinomatous hyperplasia (PCH) is a benign reactive epithelial proliferation that may be associated to lymphomas of the skin or external mucous membranes. We present a case of single lesion mycosis fungoides (Woringer-Kollop's reticulosis pagetoid) associated with PCH that was initially misdiagnosed as squamous cell carcinoma (SCC) and review all PubMed-indexed previously reported cases on lymphomas of the skin or external mucous membranes associated to PCH, SCC, and keratoacanthomas. Including our own case, we collected data of 114 cases of cutaneous or mucosal lymphoproliferative disorders associated to PCH, 3 cases associated to SCC, and other 3 cases associated to keratoacanthomas. All cases were tabulated to the following parameters whenever data was available: sex, age, previous medical conditions, number of lesions (single × multiple), site of involvement (mucosa, skin or both), clinical impression, initial equivocal histopathologic diagnosis, final diagnosis, keratinocytic atypia (presence × absence), lymphocytic atypia (presence × absence), CD30-status, and treatment.

Pseudocarcinomatous Hyperplasia Hiding Lymphomatoid Papulosis

Pseudocarcinomatous hyperplasia (PCH) is a reactive proliferation of the epidermis that can be associated with many inflammatory and neoplastic conditions. Histologically, it is characterized by irregular strands of epidermis, usually at the level of the follicular infundibulum, projecting downward into the dermis. The differentiation between a well-differentiated squamous cell carcinoma and PCH can be particularly challenging when the biopsy is superficial and the causing lesion is dermal-based. Lymphomatoid papulosis (LyP) is an uncommon, self-healing, recurrent, cutaneous T-cell lymphoma, included among the primary cutaneous CD30-positive T-cell lymphoproliferative disorders. LyP is characterized by a chronic course of years to decades that does not compromise survival, even if patients with LyP are at risk for second cutaneous or nodal lymphoid malignancies. LyP and other lymphomas are major neoplastic causes of PCH and can be misdiagnosed or completely overlooked if the PCH is particularly exuberant. We describe the case of an otherwise healthy 55-year-old man who presented with a 3-month history of erythematous papules on upper and lower limbs. A diagnosis of LyP associated with PCH was made after 3 skin biopsies. The propensity of the CD30+ cutaneous lymphoproliferative disorders to an incognito growth pattern is well recognized, and a low-magnification scanning of the histological slides can be an inappropriate approach.

Pseudocarcinomatous hyperplasia in anaplastic large cell lymphoma, a mimicker of poorly differentiated squamous cell carcinoma: report of a case and review of the literature

Pseudocarcinomatous hyperplasia can occasionally be observed in biopsies of CD30-positive lymphoproliferative disorders. It is important to be cognizant of this association, because epithelial hyperproliferation can overshadow large atypical lymphoid cells, leading to an erroneous diagnosis of squamous cell carcinoma (SCC) or keratoacanthoma. Herein, we present a case of anaplastic large cell lymphoma (ALCL) with pseudocarcinomatous hyperplasia simulating a poorly differentiated carcinoma and review the literature on this subject. Immunohistochemical staining with p63 helped delineate the infiltrating tongues of pseudocarcinomatous hyperplasia from the malignant infiltrate. We present this case to raise awareness of the potential for pseudocarcinomatous hyperplasia to occur in the setting of CD30+ lymphoproliferative disorders. Clinicians and dermatopathologists should consider the possibility of ALCL or lymphomatoid papulosis when examining lesions with features of inflamed SCC, especially if the tumor presents on a site or in a patient that is not typical of SCC.

Pseudoepitheliomatous hyperplasia mimicking invasive squamous cell carcinoma in extranodal natural killer/T-cell lymphoma: a report of 34 cases

AIMS

Pseudoepitheliomatous hyperplasia (PEH) is defined as a pattern of epidermal reaction. However, it has not yet been extensively documented in extranodal natural killer/T-cell lymphoma (ENKTL). The aim of our study was to analyse a series of ENKTLs concomitant with PEH mimicking squamous cell carcinoma (SCC).

METHODS AND RESULTS

We analysed 34 cases of ENKTL with PEH. In our study, the incidence of PEH was 3.8% in ENKTLs diagnosed over a 13-year period. All 34 cases presented with PEH, appearing as tongue-like projections of squamous epithelium into the underlying submucosa/dermis with variable depths and jagged borders. The keratinocytes sometimes showed a minor degree of cytological atypia, mostly in the stratum basale, and keratinocyte necrosis was absent. Atypical mitoses and a high nuclear/cytoplasmic ratio were absent. The submucosa and the squamous cell cords were also permeated by atypical lymphocytes.

CONCLUSIONS

ENKTL can be associated with PEH, and the atypical lymphoid cell population can be highly subtle, and therefore may be easily mistaken for SCC, leading to inappropriate therapy. A correct diagnosis requires awareness and recognition of this pitfall by recognizing the associated conditions listed above, which distinguish PEH from SCC.

Pseudocarcinomatous hyperplasia mimicking squamous cell carcinoma in a case of CD56-positive cytotoxic T-cell lymphoma

We present the case of an 84-year-old patient with a cutaneous CD56 positive cytotoxic T-cell lymphoma associated with substantial pseudocarcinomatous hyperplasia mimicking squamous cell carcinoma (SCC). The patient presented with a 7-month history of several progressive, ulcerated plaques on his right forearm. An initial biopsy showed changes consistent with a diagnosis of SCC for which the patient underwent surgical treatment. Several months later, the patient developed recurrent ulcerated plaques on the right forearm of which several biopsies were performed. The biopsies repeatedly showed marked pseudocarcinomatous hyperplasia resembling SCC. Deeper punch biopsies, however, showed a dense superficial and deep infiltrate of markedly atypical lymphocytes. Immunohistochemical analysis revealed strong positive staining for CD3, CD8, CD56 with negative stains for CD30 and Epstein-Barr virus-encoded small non-polyadenylated RNAs (EBER). Staining for beta F1 and gamma-delta T-cell receptor (γδ TCR) were both negative. This constellation was most consistent with a diagnosis of cutaneous peripheral T-cell lymphoma, unspecified in association with marked pseudocarcinomatous hyperplasia. Our case adds cutaneous peripheral T-cell lymphoma, unspecified to the list of conditions associated with pseudocarcinomatous hyperplasia (PCH) and illustrates once again the potential pitfalls of distinguishing marked pseudocarcinomatous hyperplasia from SCC.

Non-mycosis fungoides cutaneous T-cell lymphomas: report of the 2011 Society for Hematopathology/European Association for Haematopathology workshop

Primary cutaneous T-cell lymphomas (CTCL) excluding mycosis fungoides (MF) were discussed in 2 sessions of the 2011 Society for Hematopathology/ European Association of Haematopathology Workshop, Los Angeles, CA. Session 2 focused on primary cutaneous CD30+ T-cell lymphoproliferative disorders and their differential diagnosis, including systemic CD30+ T-cell lymphoma secondarily infiltrating the skin. Interesting features like special morphologic variants and atypical phenotypes were presented. In addition, the possibility of rare ALK+ primary cutaneous lymphomas was discussed. Session 3 examined other more uncommon non-MF CTCLs, including subcutaneous panniculitis-like T-cell lymphoma, extranodal NK/T-cell lymphoma, hydroa vacciniforme-like T-cell lymphoma, and rare subtypes of primary cutaneous peripheral T-cell lymphoma, not otherwise specified. In addition, systemic T-cell lymphomas involving the skin secondarily, such as angioimmunoblastic T-cell lymphoma, were included in this session. In this report, novel findings, areas of special interest, and diagnostic challenges emerging from the cases submitted to the workshop will be highlighted. The necessity to integrate histologic, immunophenotypical, genetic, and in particular, clinical data to arrive at the correct diagnosis, and subsequently provide adequate treatment, is emphasized.

Spontaneous regression of primary diffuse large B-cell lymphoma, leg type

Primary cutaneous diffuse large B-cell lymphoma, leg type (PCLBCL LT) accounts for approximately 20% of all primary cutaneous B-cell lymphomas and tends to present as infiltrated nodules, tumors, and plaques on the legs in the elderly. Unlike other primary cutaneous large B-cell lymphomas, it has a poor prognosis and tends to require treatment with systemic chemotherapy. We present the case of an 82-year-old patient with a 1-year history of nodules and plaques on her right leg. Biopsy led to a diagnosis of PCLBCL LT and the lesions resolved without treatment within 1 month of the first visit. This is an atypical course of PCLBCL LT and we believe that it is the first such case to be reported in the literature.

Comments on cutaneous lymphomas: since the WHO-2008 classification to present

The last classification of lymphomas of the World Health Organization in 2008 made a few changes from the preceding classification. Although useful, at the same time, it has posed new questions, concerns, and dilemmas which have been raised in the literature. The current report highlights some of these controversies, of each of these primary cutaneous entities, going through cutaneous mature T-cell and NK-cell neoplasms, mature B-cell neoplasms, precursor neoplasms, and other entities, which for several reasons do not fit in the previous categories. It also reviews some advances on many of these lymphomas published in the last 2 years.

Pseudoepitheliomatous hyperplasia: a review

Pseudoepitheliomatous hyperplasia (PEH) is a benign condition, characterized by hyperplasia of the epidermis and adnexal epithelium, closely simulating squamous cell carcinoma. PEH may be present in a number of conditions characterized by prolonged inflammation and/or chronic infection, as well as in association with many cutaneous neoplasms. Herein, we review different inflammatory, infectious, and neoplastic skin diseases, in which florid epidermal hyperplasia is a prominent histopathologic feature, and introduce a systematic approach in the interpretation of PEH.

Anaplastic large cell lymphoma: twenty-five years of discovery

CONTEXT

The year 2010 commemorates the 25th year since the seminal publication by Karl Lennert and Harald Stein and others in Kiel, West Germany, describing an unusual large cell lymphoma now known as anaplastic large cell lymphoma (ALCL). Investigators at many universities and hospitals worldwide have contributed to our current in-depth understanding of this unique peripheral T-cell lymphoma, which in its systemic form, principally occurs in children and young adults.

OBJECTIVE

To summarize our current knowledge of the clinical and pathologic features of systemic and primary cutaneous ALCL. Particular emphasis is given to the biology and pathogenesis of ALCL.

DATA SOURCES

Search of the medical literature (Ovid MEDLINE In-Process & Other Non-Indexed Citations and Ovid MEDLINE: 1950 to Present [National Library of Medicine]) and more than 20 years of diagnostic experience were used as the source of data for review.

CONCLUSIONS

Based on immunostaining for activation antigen CD30 and the presence of dysregulation of the anaplastic lymphoma kinase gene (2p23), the diagnosis of ALCL has become relatively straightforward for most patients. Major strides have been made during the last decade in our understanding of the complex pathogenesis of ALCL. Constitutive NPM-ALK signaling has been shown to drive oncogenesis via an intricate network of redundant and interacting pathways that regulate cell proliferation, cell fate, and cytoskeletal modeling. Nevertheless, pathomechanistic, therapeutic, and diagnostic challenges remain that should be resolved as we embark on the next generation of discovery.