CD30 antigen expression in cutaneous inflammatory infiltrates of scabies: a dynamic immunophenotypic pattern that should be distinguished from lymphomatoid papulosis

Updates in pathobiological aspects of anaplastic large cell lymphoma

Anaplastic large cell lymphomas (ALCL) encompass several distinct subtypes of mature T-cell neoplasms that are unified by the expression of CD30 and anaplastic cytomorphology. Identification of the cytogenetic abnormality t(2;5)(p23;q35) led to the subclassification of ALCLs into ALK+ ALCL and ALK- ALCL. According to the most recent World Health Organization (WHO) Classification of Haematolymphoid Tumours as well as the International Consensus Classification (ICC) of Mature Lymphoid Neoplasms, ALCLs encompass ALK+ ALCL, ALK- ALCL, and breast implant-associated ALCL (BI-ALCL). Approximately 80% of systemic ALCLs harbor rearrangement of ALK, with NPM1 being the most common partner gene, although many other fusion partner genes have been identified to date. ALK- ALCLs represent a heterogeneous group of lymphomas with distinct clinical, immunophenotypic, and genetic features. A subset harbor recurrent rearrangement of genes, including TYK2, DUSP22, and TP63, with a proportion for which genetic aberrations have yet to be characterized. Although primary cutaneous ALCL (pc-ALCL) is currently classified as a subtype of primary cutaneous T-cell lymphoma, due to the large anaplastic and pleomorphic morphology together with CD30 expression in the malignant cells, this review also discusses the pathobiological features of this disease entity. Genomic and proteomic studies have contributed significant knowledge elucidating novel signaling pathways that are implicated in ALCL pathogenesis and represent candidate targets of therapeutic interventions. This review aims to offer perspectives on recent insights regarding the pathobiological and genetic features of ALCL.

Deep Sequencing of Immunoglobulin Genes Identifies a Very Low Percentage of Monoclonal B Cells in Primary Cutaneous Marginal Zone Lymphomas with CD30-Positive Hodgkin/Reed–Sternberg-like Cells

The spectrum of cutaneous CD30-positive lymphoproliferative disorders encompasses both inflammatory and neoplastic conditions. CD30+ Hodgkin and Reed–Sternberg-like cells have been occasionally reported in primary cutaneous marginal zone lymphoma, where they are thought to represent a side neoplastic component within a dominant background of lymphomatous small B cells. Herein, we describe the histological and molecular findings of three cases of primary cutaneous marginal zone lymphomas with CD30+ H/RS cells, in which next-generation sequencing analysis revealed the clonal population to consist in less than 5% of the cutaneous B-cell infiltrate, providing a thought-provoking focus on a possible main role for CD30+ cells in primary cutaneous marginal zone lymphoproliferations.

Pseudomalignancies in Children: Histological Clues, and Pitfalls to Be Avoided

The term “pseudomalignancy” covers a large, heterogenous group of diseases characterized by a benign cellular proliferation, hyperplasia, or infiltrate that resembles a true malignancy clinically or histologically. Here, we (i) provide a non-exhaustive review of several inflammatory skin diseases and benign skin proliferations that can mimic a malignant neoplasm in children, (ii) give pathologists some helpful clues to guide their diagnosis, and (iii) highlight pitfalls to be avoided. The observation of clinical–pathological correlations is often important in this situation and can sometimes be the only means (along with careful monitoring of the disease’s clinical course) of reaching a firm diagnosis.

Eruptive ulcerative follicular spicules heralding progression of smoldering multiple myeloma

Herein, we describe a patient with immunoglobulin G (IgG)-lambda smoldering multiple myeloma with translocation t(4:14) who developed widespread ulcerative horny-like spicules, heralding rapid progression to overt myeloma requiring aggressive chemotherapy and autologous stem cell transplantation. The serum abnormal immunoglobulin in the blood was cryoglobulin, which typically precipitates in the tissues at low temperatures causing inflammation and tissue damage. Histopathological changes, observed in lesions at different evolutionary stages, evidenced columns of horny-like eosinophilic homogeneous material, immunoreactive for IgG lambda, protruding from the dilated and/or distorted follicular openings or acrosyringia and small vessel thrombotic vasculopathy and vasculitis in concert with an inflammatory neutrophilic and lymphocytic reaction. Biochemical investigations on material from a spicule and ulcero-necrotic lesion revealed cryoprecipitates containing IgG-lambda with electrophoretic characteristics identical to those of the serum dysprotein. Our findings suggest that the formation of spicules and development of ulcerative lesions are a part of the same clinical spectrum where the cold-dependent precipitation of the immunogenic dysprotein, both in the skin vessels and hair follicle infundibula, play a major pathogenetic role. Whether this highly characteristic paraneoplastic dermatosis can identify patients with high-risk cytogenetic abnormalities and be incorporated into prognostic models, applicable early on in the course of myeloma, warrants further investigation.

CD30+ Lymphoproliferative Disorders of the Skin

Primary cutaneous CD30⁺ lymphoproliferative disorders encompass lymphomatoid papulosis (LyP), primary cutaneous anaplastic large cell lymphoma (pcALCL), and indeterminate cases. LyP is a benign disorder characterized by recurrent crops of red or violaceous papulonodules. Patients with LyP are at an increased risk of a secondary malignancy. pcALCL is characterized by a solitary red to violaceous nodule or tumor larger than 20 mm. LyP is benign, is limited to the skin, and self-resolves, with a 5-year survival rate of 100%; pcALCL is limited to the skin and responsive to directed therapies, with a 5-year survival rate of over 95%. Aggressive chemotherapeutic regimens should be avoided.

Linear Folliculotropic CD30-Positive Lymphomatoid Drug Reaction

We report a unique case of probable drug-induced CD30-positive lymphomatoid reaction. A 58-year-old woman presented with bilateral facial eruptions of 3 weeks duration composed of erythematosus papules in a linear distribution. The pathological features demonstrated a dense dermal and follicular infiltrate of many medium- to large-sized atypical CD30-positive lymphoid cells. The rash resolved rapidly after discontinuation of her medication 1 week later and did not recur. This case highlights the importance of clinicopathological correlation.

Cutaneous Pseudolymphomas

The term cutaneous pseudolymphoma refers to benign reactive lymphoid proliferations in the skin that simulate cutaneous lymphomas. It is a purely descriptive term that encompasses various reactive conditions with a varied etiology, pathogenesis, clinical presentation, histology, and behavior. We present a review of the different types of cutaneous pseudolymphoma. To reach a correct diagnosis, it is necessary to contrast clinical, histologic, immunophenotypic, and molecular findings. Even with these data, in some cases only the clinical course will confirm the diagnosis, making follow-up essential.

Temporal expression and DNA hypomethylation profile of CD30 in Marek's disease virus-infected chicken spleens

Marek's disease (MD) is a viral neoplastic disease of chickens caused by Marek's disease virus (MDV), which is serious threat to worldwide poultry industry. Our previous studies showed that the CD30 gene was hypomethylated in MD lymphoma. In this study, we further analyzed differential expression patterns and methylation levels of the CD30 gene between MDV-infected and noninfected spleens at 4, 7, 14, 21, and 28 d postinfection (dpi). The results showed that the expression of CD30 in MDV-infected spleens was significantly lower than that in noninfected spleens at 4 dpi. The expression of CD30 did not present significant difference between MDV-infected and noninfected spleens at 7 and 14 dpi. However, an increased expression of CD30 was presented in MDV-infected spleens at both 21 and 28 dpi. Simultaneously, CD30 showed a lower DNA methylation level in MDV-infected spleens at 14, 21, and 28 dpi. The results indicated that CD30 gene was involved in the whole process of MD tumorigenesis and upregulated expression of CD30 in MDV-infected spleens might be attributed to the hypomethylation of promoter of CD30 gene.

Histopathological features in both the eschar and erythematous lesions of Tsutsugamushi Disease: identification of CD30+ cell infiltration in Tsutsugamushi disease

Tsutsugamushi disease is an acute febrile infectious disease caused by Rickettsia tsutsugamushi. An infection is heralded by the presence of an eschar at the site of the inoculating chigger bite and followed by the development of a disseminated erythematous macular rash. CD30 expression is found in anaplastic large cell lymphoma; however, expression in nonneoplastic cutaneous disorders, such as atopic dermatitis, drug reactions, scabies, and various infectious diseases, has also been reported. Study of the cutaneous histopathology of tsutsugamushi disease has been limited. In this study, we performed biopsies of both the eschar and erythematous lesions of 15 cases of tsutsugamushi disease to assess the histopathological changes including the CD3, CD4, CD20, CD30, and CD68 reactivity. Twelve women and 3 men were included with an age range from 21 to 73 years. The most common location of the eschar was the trunk (53.3%). The histological features showed increased leukocytoclastic vasculitis in the eschar (93.3%) compared with the erythematous lesions (33.3%); basal vacuolar changes were more common in the erythematous (100%) than in the eschar lesions (20%). The inflammatory infiltrate had a majority of CD3- and CD68-positive cells. Seven erythematous lesions and 7 eschar lesions showed atypical cells that were CD30-positive cells. Here, we report on the cutaneous histopathology and pattern of inflammatory infiltrates of tsutsugamushi disease. Leukocytoclastic vasculitis and basal vacuolar changes were the characteristic features of the eschar and the erythematous lesions, respectively. In addition, CD30-positive cell infiltration was identified for the first time in this disease.

Epithelioid hemangioma (angiolymphoid hyperplasia with eosinophilia) arising on the extremities

BACKGROUND

Epithelioid hemangioma (EH) is a benign vascular proliferation usually accompanied by a mixed inflammatory infiltrate.

METHODS

Skin biopsy specimens from four patients with EH on the extremities were studied. Architecture, extent of vascular proliferation and the presence of epithelioid endothelial cells were evaluated. The features of the inflammatory infiltrate were also assessed, including the distribution, depth, predominant cell type, presence of germinal centers, and distribution and number of CD30+ cells.

RESULTS

All cases showed the typical lobular pattern of small vessels centered about a 'feeder' vessel. Larger vessels were lined by epithelioid endothelial cells. The mixed inflammatory infiltrate was nodular, perivascular and periadnexal. Germinal centers were seen in two cases. Large activated CD30+ lymphocytes were seen in all cases.

CONCLUSIONS

EH can lead to diagnostic confusion with cutaneous lymphoma and other entities, especially when its mixed inflammatory infiltrate predominates over its vascular component and contains large activated CD30+ lymphocytes. Awareness that the presence of CD30+ activated lymphocytes is not specific for lymphoma and recognition of the vascular component is critical for proper diagnosis of EH.

Langerhans cell hyperplasia in scabies: a mimic of Langerhans cell histiocytosis

AIM

In the absence of mites, the histologic diagnosis of human scabies can be difficult. Scabies can mimic a variety of inflammatory and lymphoproliferative disorders. It is under-recognized that scabies can also mimic Langerhans cell histiocytosis.

METHODS

Sixteen examples of scabies were reviewed histologically and immunohistochemically (CD1a, CD3, CD20, CD30 and S100).

RESULTS

Immunohistochemical labeling showed florid CD1a and S100 positivity in most cases, indicative of Langerhans cell hyperplasia. Scattered CD30+ lymphocytes were also typically present, within a dense infiltrate, primarily composed of T lymphocytes and eosinophils.

CONCLUSION

Because of the prominent CD1a+/S100+ component, scabies can mimic Langerhans cell histiocytosis. This finding should be considered in conjunction with scattered CD30+ cells and clinical features to avoid misdiagnosis.

Eosinophilic ulcer of the oral mucosa: another histological simulator of CD30+ lymphoproliferative disorders

Eosinophilic ulcer of the oral mucosa (EUOM), also known as traumatic ulcerative granuloma with stromal eosinophilia or Riga-Fede disease, is an uncommon benign self-limited lesion poorly described in the dermatological literature. It probably includes a spectrum of related disorders presenting as an ulcer with elevated indurated borders affecting the tongue, oral mucosa or lip. Histopathological findings are characteristic and consist of eosinophil-rich mixed infiltrates accompanied by a population of large mononuclear cells whose origins have been a matter of debate. Immunohistochemical studies of these cells have suggested a myofibroblastic or histiocytic origin. We present a 93-year-old woman with two episodes of self-healing ulcers on the upper lip and on the lingual mucosa, respectively. Histopathological findings on both biopsies were consistent with EUOM and showed the presence of large atypical CD30+ lymphocytes. Some recent reports have also shown positivity for the CD30 antigen, raising the possibility that a subset of EUOM could be included within the spectrum of CD30+ lymphoproliferative disorders. This finding most likely suggests that EUOM can represent another histological simulator of CD30+ lymphoproliferative disorders.

CD30+ lymphoproliferative disorders: histopathology, differential diagnosis, new variants, and simulators

CD30+ lymphoproliferative disorders of the skin (CD30+ LPD) represent a well-defined spectrum of primary cutaneous T-cell lymphomas which have been recognized as distinct entities in recent lymphoma classifications. Lymphomatoid papulosis and anaplastic large-cell lymphoma share the expression of CD30 antigen as a common phenotypic hallmark but differ in regard to their clinical and histologic features as well as their biologic behavior. This article summarizes the histologic features of CD30+ LPD and presents recently identified new clinicopathologic variants of CD30+ LPD. There is an increasing number of reactive inflammatory disorders and neoplastic diseases which are composed of or contain a significant number of CD30+ cells and mimic LyP or anaplastic large cell lymphoma clinically or histologically. Differential diagnostic considerations focus on other lymphoproliferative processes with CD30+ tumor cells as well as non-lymphoid neoplasms and inflammatory simulators. The term CD30+ pseudolymphoma is proposed to designate inflammatory processes with CD30+ T cells. The final diagnosis of CD30+ LPD is based on a synthesis of clinical, histologic, phenotypic, and molecular genetic findings.

Histopathologic Features of Cutaneous Herpes Virus Infections (Herpes Simplex, Herpes Varicella/Zoster)

Cutaneous eruptions caused by herpes simplex 1/2 (HSV-1/2) and herpes varicella/zoster (VZV) represent common dermatoses. In some cases, they present with atypical clinical and/or histopathologic features, including presence of dense lymphoid infiltrates with atypical lymphocytes simulating cutaneous lymphomas. In this study, we reviewed the biopsy specimens of 65 patients (33 males, 32 females; mean age, 61.2 years; median age, 62 years; age range, 19-96 years) with cutaneous eruptions caused by HSV-1/2 or VZV. Histologic examination revealed several atypical findings, including presence of dense lymphoid infiltrates, angiotropism, and atypical lymphocytes simulating malignant lymphoma. Immunohistochemistry performed in 22 cases showed a predominant T-cell infiltrate, in the majority of cases with variable numbers of CD30+ and CD56+ cells. Two cases with a pseudolymphomatous appearance and small clusters of CD30+ cells revealed a monoclonal population of T lymphocytes by PCR analysis, underlying the difficulties in classifying some of these cases correctly. Our study indicates that cutaneous herpes infections can exhibit several atypical histopathologic, immunohistochemical, and molecular features, and that in given cases accurate clinicopathologic correlation and short-term follow-up controls are necessary for differentiation from cutaneous lymphomas.

Lymphomatoid papulosis in an HIV-positive man

Lymphomatoid papulosis (LyP) is a rare cutaneous lymphoproliferative condition characterized by a chronic, recurrent eruption of papules and nodules that undergo spontaneous regression. The disorder is usually clinically benign; with a minority of cases progressing to malignant lymphoma. LyP is divided into two subtypes based on histologic appearance. Type A resembles Hodgkin's disease with up to 20% of large CD30+ lymphocytes. Type B resembles mycosis fungoides showing an infiltrate of CD4+ lymphocytes and scattered CD30+ cells. Clinically LyP often resembles pityriasis lichenoides et varioliformis acuta but has a strikingly different histological appearance. Histologically, LyP resembles lymphoma (anaplastic T-cell or Hodgkin's) but is distinguished by its benign course. Here we present a case of LyP in a severely immune-repressed HIV-positive patient. This patient presented with pruritic papules involving the upper extremities and a CD4+ T-cell count of 4. Histopathologic examination showed a dense superficial dermal infiltrate comprising normal-sized lymphocytes admixed with larger lymphocytes. Immunophenotyping showed most of the lymphocytes to be CD3+ (T cells). The scattered larger cells were CD30+. The smaller lymphocytes were CD8+ rather than CD4+ as expected for non-HIV-appointed LyP. This may be because of the immune disregulation of HIV disease and the absolute and relative paucity of CD4+ T cells relative to CD8+ T cells.

Primary cutaneous CD30-positive lymphoproliferative disorders

Primary cutaneous CD30-positive (anaplastic) large T-cell lymphoma and lymphomatoid papulosis have many overlapping clinical, histologic, and immunophenotypic features. These entities are currently considered as parts of a spectrum of primary cutaneous CD30-positive lymphoproliferative disorders. We provide the clinician with practical guidelines for the diagnosis, management, and treatment of patients within this spectrum of primary cutaneous CD30-positive lymphoproliferative disorders. Most patients within this spectrum of disease have an excellent prognosis. Multi-agent chemotherapy should be reserved for patients who have extracutaneous disease.