Melanocytic Matricoma: A Potential Mimic of Malignant Melanoma.

Melanocytic matricoma is a rare dermal tumor that typically presents on the sun-damaged skin of older patients. While there is controversy in the literature regarding the proper characterization of this tumor, there are certain histological and immunohistochemical features that have been described. This report presents a case of melanocytic matricoma with several unusual features that were initially feared to be malignant melanoma. Careful histologic and immunohistochemical analysis was required to rule out malignant melanoma and make the correct diagnosis. Given the rarity of melanocytic matricoma and the potential for it to mimic malignant melanoma, it is important for pathologists to keep melanocytic matricoma on the differential and be aware of the clinical, histological, and immunohistochemical features of this tumor.

Ileo-Colonic Fistula Due to Diffuse Large B Cell Lymphoma: Unusual Presentation of a Rare Disease.

Malignant ileocolonic fistulas have seldom been documented as complications of a primary gastrointestinal lymphoma (PGIL) such as aggressive diffuse large B cell lymphoma (DLBCL). These fistulas are frequently misdiagnosed due to the nonspecific clinical presentation. Currently, there is no standardized treatment approach, although a couple have been suggested with varying outcomes. We describe a case of DLBCL complicated with a malignant ileocolonic fistula in a 55-year-old male with a favorable outcome after surgery and chemotherapy.

Molecular profiling reveals a hypoxia signature in breast implant-associated anaplastic large cell lymphoma.

Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is a recently characterized T-cell malignancy that has raised significant patient safety concerns and led to worldwide impact on the implants used and clinical management of patients undergoing reconstructive or cosmetic breast surgery. Molecular signatures distinguishing BIA-ALCL from other ALCLs have not been fully elucidated and classification of BIA-ALCL as a WHO entity remains provisional. We performed RNA sequencing and gene set enrichment analysis comparing BIA-ALCLs to non-BIA-ALCLs and identified dramatic upregulation of hypoxia signaling genes including the hypoxia-associated biomarker CA9 (carbonic anyhydrase-9). Immunohistochemistry validated CA9 expression in all BIA-ALCLs, with only minimal expression in non-BIA-ALCLs. Growth induction in BIA-ALCL-derived cell lines cultured under hypoxic conditions was proportional to up-regulation of CA9 expression, and RNA sequencing demonstrated induction of the same gene signature observed in BIA-ALCL tissue samples compared to non-BIA-ALCLs. CA9 silencing blocked hypoxia-induced BIA-ALCL cell growth and cell cycle-associated gene expression, whereas CA9 overexpression in BIA-ALCL cells promoted growth in a xenograft mouse model. Furthermore, CA9 was secreted into BIA-ALCL cell line supernatants and was markedly elevated in human BIA-ALCL seroma samples. Finally, serum CA9 concentrations in mice bearing BIA-ALCL xenografts were significantly elevated compared to control serum. Together, these findings characterize BIA-ALCL as a hypoxia-associated neoplasm, likely attributable to the unique microenvironment in which it arises. These data support classification of BIA-ALCL as a distinct entity and uncover opportunities for investigating hypoxia-related proteins such as CA9 as novel biomarkers and therapeutic targets in this disease.

Recurrent MSC E116K mutations in ALK-negative anaplastic large cell lymphoma.

Anaplastic large cell lymphomas (ALCLs) represent a relatively common group of T-cell non-Hodgkin lymphomas (T-NHLs) that are unified by similar pathologic features but demonstrate marked genetic heterogeneity. ALCLs are broadly classified as being anaplastic lymphoma kinase (ALK)+ or ALK-, based on the presence or absence of ALK rearrangements. Exome sequencing of 62 T-NHLs identified a previously unreported recurrent mutation in the musculin gene, MSC E116K, exclusively in ALK- ALCLs. Additional sequencing for a total of 238 T-NHLs confirmed the specificity of MSC E116K for ALK- ALCL and further demonstrated that 14 of 15 mutated cases (93%) had coexisting DUSP22 rearrangements. Musculin is a basic helix-loop-helix (bHLH) transcription factor that heterodimerizes with other bHLH proteins to regulate lymphocyte development. The E116K mutation localized to the DNA binding domain of musculin and permitted formation of musculin-bHLH heterodimers but prevented their binding to authentic target sequence. Functional analysis showed MSCE116K acted in a dominant-negative fashion, reversing wild-type musculin-induced repression of MYC and cell cycle inhibition. Chromatin immunoprecipitation-sequencing and transcriptome analysis identified the cell cycle regulatory gene E2F2 as a direct transcriptional target of musculin. MSCE116K reversed E2F2-induced cell cycle arrest and promoted expression of the CD30-IRF4-MYC axis, whereas its expression was reciprocally induced by binding of IRF4 to the MSC promoter. Finally, ALCL cells expressing MSC E116K were preferentially targeted by the BET inhibitor JQ1. These findings identify a novel recurrent MSC mutation as a key driver of the CD30-IRF4-MYC axis and cell cycle progression in a unique subset of ALCLs.

Molecular profiling reveals immunogenic cues in anaplastic large cell lymphomas with DUSP22 rearrangements.

Anaplastic large cell lymphomas (ALCLs) are CD30-positive T-cell non-Hodgkin lymphomas broadly segregated into ALK-positive and ALK-negative types. Although ALK-positive ALCLs consistently bear rearrangements of the ALK tyrosine kinase gene, ALK-negative ALCLs are clinically and genetically heterogeneous. About 30% of ALK-negative ALCLs have rearrangements of DUSP22 and have excellent long-term outcomes with standard therapy. To better understand this group of tumors, we evaluated their molecular signature using gene expression profiling. DUSP22-rearranged ALCLs belonged to a distinct subset of ALCLs that lacked expression of genes associated with JAK-STAT3 signaling, a pathway contributing to growth in the majority of ALCLs. Reverse-phase protein array and immunohistochemical studies confirmed the lack of activated STAT3 in DUSP22-rearranged ALCLs. DUSP22-rearranged ALCLs also overexpressed immunogenic cancer-testis antigen (CTA) genes and showed marked DNA hypomethylation by reduced representation bisulfate sequencing and DNA methylation arrays. Pharmacologic DNA demethylation in ALCL cells recapitulated the overexpression of CTAs and other DUSP22 signature genes. In addition, DUSP22-rearranged ALCLs minimally expressed PD-L1 compared with other ALCLs, but showed high expression of the costimulatory gene CD58 and HLA class II. Taken together, these findings indicate that DUSP22 rearrangements define a molecularly distinct subgroup of ALCLs, and that immunogenic cues related to antigenicity, costimulatory molecule expression, and inactivity of the PD-1/PD-L1 immune checkpoint likely contribute to their favorable prognosis. More aggressive ALCLs might be pharmacologically reprogrammed to a DUSP22-like immunogenic molecular signature through the use of demethylating agents and/or immune checkpoint inhibitors.

Collagenous Gastritis in a Young Female With IgA Deficiency.

Collagenous gastritis, without colonic involvement, is exceptionally rare. It is not known to be associated with IgA deficiency and scleroderma. This is the first report of this type of association. We present a 26-year-old white female with a past medical history of gastroesophageal reflux disease and scleroderma. She was evaluated for complaints of abdominal pain and diarrhea. Esophagogastroduodenoscopy showed gastritis and duodenitis. Colonoscopy was normal. The histopathological report showed collagenous gastritis and focal lymphocytic duodenitis. A definitive treatment has not been established for this condition. Reporting such cases furthers understanding of the disease and will help to establish diagnostic criteria and to develop therapeutic strategies.

Expression of p63 protein in anaplastic large cell lymphoma: implications for genetic subtyping.

Anaplastic large cell lymphomas (ALCLs) are CD30-positive T-cell non-Hodgkin lymphomas that bear chromosomal rearrangements of the TP53 homologue TP63 in a subset of cases that demonstrate aggressive clinical behavior. In the present study, we examined the relationship between p63 protein expression by immunohistochemistry and the results of fluorescence in situ hybridization using TP63 probes in 116 ALCLs. We also determined the relative expression of full-length TAp63 and truncated ΔNp63 isoforms (eg, p40) in ALCL cell lines and a subset of clinical cases. Overall, 35.3% of ALCLs were positive for p63 protein. Primary cutaneous and anaplastic lymphoma kinase-negative ALCLs were positive more frequently than anaplastic lymphoma kinase-positive ALCLs (P=.0034). As previously reported, cases with TP63 gene rearrangements expressed p63 uniformly. p63 expression in nonrearranged cases was associated with extra copies of TP63 on 3q28 (P<.0001). Extra copies of TP63 correlated with extra copies of the DUSP22 locus on 6p25.3 (P<.0001). Results of immunohistochemistry, Western blotting, and RNA sequencing indicated that p63 expression in nonrearranged cases was entirely attributable to TAp63 isoforms. Taken together, these findings indicate that ALCLs without TP63 rearrangements may express TAp63 isoforms of p63 and that this expression is associated with extra copies of TP63, probably due to widespread genomic copy number abnormalities rather than focal gains. Immunohistochemistry for p63 in ALCL is not specific for TP63 rearrangements but is useful clinically as a screening test to select cases for further testing by fluorescence in situ hybridization. Immunohistochemistry for ΔNp63 (p40) is not informative in the evaluation of ALCL.

Extra-Adrenal Myelolipoma Containing Small Lymphocytic Lymphoma/Chronic Lymphocytic Leukemia: A Case Report and Review of the Literature.

Myelolipoma is a benign tumor consisting of mature fat interspersed with hematopoietic elements resembling bone marrow. The vast majority occurs within the adrenal glands, but several cases of extra-adrenal myelolipomas (EAMLs) have been reported. We report a case of a 64-year-old male who presented with complaint of lower abdominal discomfort. CT scan of abdomen and pelvis showed a 6 cm × 5 cm, well-circumscribed, predominantly fatty mass in the presacral region. Histological examination of the pelvic mass revealed a myelolipoma heavily infiltrated by small lymphoid cell aggregates with immunophenotypic features of small lymphocytic lymphoma/chronic lymphocytic leukemia (SLL/CLL). Review of the literature revealed that there is only one published report of SLL/CLL involving a myelolipoma, which was also an extra-adrenal myelolipoma, and, therefore, our case is the second case of a SLL/CLL involving a myelolipoma that is an extra-adrenal myelolipoma. Extra-adrenal myelolipomas seem to the preferred myelolipomas for involvement by SLL/CLL.

Morphologic Features of ALK-negative Anaplastic Large Cell Lymphomas With DUSP22 Rearrangements.

Systemic anaplastic large cell lymphomas (ALCLs) are classified into ALK-positive and ALK-negative types. We recently reported that ALK-negative ALCLs are genetically heterogenous. The largest subset, representing 30% of cases, had rearrangements of the DUSP22 locus. These cases had favorable outcomes similar to ALK-positive ALCL, and superior to other ALK-negative ALCLs. Here, we examined the morphologic features of these cases in more detail. First, we conducted blinded review of hematoxylin and eosin slides of 108 ALCLs from our previous study, scoring cases for the presence of 3 histologic patterns and 5 cell types. Cases then were unblinded and re-reviewed to understand these features further. DUSP22-rearranged ALCLs were more likely than other ALK-negative ALCLs to have so-called doughnut cells (23% vs. 5%; P=0.039), less likely to have pleomorphic cells (23% vs. 49%; P=0.042), and nearly always (95%) had areas with sheet-like growth (common pattern). To examine the reproducibility of these findings, we conducted blinded review of hematoxylin and eosin slides of 46 additional ALK-negative ALCLs using a 0 to 3 scoring system to predict likelihood of DUSP22 rearrangement, the results of which correlated strongly with subsequent findings by fluorescence in situ hybridization (P<0.0001). Although all ALCLs share certain morphologic features, ALCLs with DUSP22 rearrangements show significant differences from other ALK-negative ALCLs, typically showing sheets of hallmark cells with doughnut cells and few large pleomorphic cells. These morphologic findings and our previous outcome data suggest that ALK-positive ALCLs and DUSP22-rearranged ALCLs represent prototypical ALCLs, whereas ALCLs lacking rearrangements of both DUSP22 and ALK require further study.

Ewing's sarcoma of the cervix, a diagnostic dilemma: a case report and review of the literature.

INTRODUCTION: Ewing's sarcoma belongs to a spectrum of neoplastic diseases known as Ewing's family of tumors. This family of tumors is usually seen in osseous sites. Ewing's sarcoma of the cervix is extremely rare, with only 18 cases reported in the English literature. The immunohistochemical profile of Ewing's sarcoma overlaps with other malignancies like small cell carcinoma. The rarity and complex pathologic picture of Ewing's sarcoma of the cervix creates the potential for misdiagnosis. Hence, we believe this case needs to be reported to add to the available literature. CASE PRESENTATION: A 49-year-old white Caucasian woman presented with vaginal bleeding. A pelvic examination revealed a cystic lesion arising from her cervix. Examination of a biopsy specimen revealed a poorly differentiated neoplasm, with sheets of small hyperchromatic cells, staining weakly for neuroendocrine markers. She was diagnosed with small cell carcinoma and started on concurrent chemotherapy and radiation. However, additional positive immunostaining for CD99 was strongly suggestive of Ewing's sarcoma. Fluorescence in situ hybridization revealed ESWR1 gene rearrangement, confirming Ewing's sarcoma. Our patient underwent surgery, which confirmed stage IIB Ewing's sarcoma. She received adjuvant chemotherapy but died from progressive metastatic disease after four cycles. CONCLUSION: With early diagnosis and appropriate treatment, Ewing's sarcoma of the cervix can be a potentially curable disease. However, owing to overlapping clinical and histopathological features, the diagnosis poses a challenge to oncologists and pathologists. This article guides pathologists to consider Ewing's sarcoma in the differential diagnosis of small cell carcinoma with weak staining for neuroendocrine markers. This literature review will benefit oncologists encountering this rare entity.

Giant Hemosiderotic Dermatofibroma: The Largest Giant Dermatofibroma Reported to Date.

Dermatofibroma (DF) is a relatively common benign fibrohistiocytic soft tissue tumor. It has a slightly greater incidence amongst females and typically presents itself during the midadult life as a slowly growing, firm dermal nodule, usually smaller than 2 cm in diameter, on the lower extremities. Giant DF is a rare clinical variant of DF characterized by unusually large size (>5 cm), which mimics malignant soft tissue tumor clinically. Twenty-six cases of giant DF have been reported so far. One of these giant DFs was a giant hemosiderotic DF. We report herein a case of a 47-year-old woman who presented with the largest DF reported in the literature to date. It was hemosiderotic.

Expression of the chemokine receptor gene, CCR8, is associated With DUSP22 rearrangements in anaplastic large cell lymphoma.

Anaplastic large cell lymphoma (ALCL) is one of the most common T-cell non-Hodgkin lymphomas and has 2 main subtypes: an anaplastic lymphoma kinase (ALK)-positive subtype characterized by ALK gene rearrangements and an ALK-negative subtype that is poorly understood. We recently identified recurrent rearrangements of the DUSP22 locus on 6p25.3 in both primary cutaneous and systemic ALK-negative ALCLs. This study aimed to determine the relationship between these rearrangements and expression of the chemokine receptor gene, CCR8. CCR8 has skin-homing properties and has been suggested to play a role in limiting extracutaneous spread of primary cutaneous ALCLs. However, overexpression of CCR8 has also been reported in systemic ALK-negative ALCLs. As available antibodies for CCR8 have shown lack of specificity, we examined CCR8 expression using quantitative real-time PCR in frozen tissue and RNA in situ hybridization (ISH) in paraffin tissue. Both approaches showed higher CCR8 expression in ALCLs with DUSP22 rearrangements than in nonrearranged cases (PCR: 19.5-fold increase, P=0.01; ISH: 3.3-fold increase, P=0.0008). CCR8 expression was not associated with cutaneous presentation, cutaneous biopsy site, or cutaneous involvement during the disease course. These findings suggest that CCR8 expression in ALCL is more closely related to the presence of DUSP22 rearrangements than to cutaneous involvement and that the function of CCR8 may extend beyond its skin-homing properties in this disease. This study also underscores the utility of RNA-ISH as a paraffin-based method for investigating gene expression when reliable antibodies for immunohistochemical analysis are not available.

ALK-negative anaplastic large cell lymphoma is a genetically heterogeneous disease with widely disparate clinical outcomes.

Anaplastic lymphoma kinase (ALK)-negative anaplastic large cell lymphoma (ALCL) is a CD30-positive T-cell non-Hodgkin lymphoma that morphologically resembles ALK-positive ALCL but lacks chromosomal rearrangements of the ALK gene. The genetic and clinical heterogeneity of ALK-negative ALCL has not been delineated. We performed immunohistochemistry and fluorescence in situ hybridization on 73 ALK-negative ALCLs and 32 ALK-positive ALCLs and evaluated the associations among pathology, genetics, and clinical outcome. Chromosomal rearrangements of DUSP22 and TP63 were identified in 30% and 8% of ALK-negative ALCLs, respectively. These rearrangements were mutually exclusive and were absent in ALK-positive ALCLs. Five-year overall survival rates were 85% for ALK-positive ALCLs, 90% for DUSP22-rearranged ALCLs, 17% for TP63-rearranged ALCLs, and 42% for cases lacking all 3 genetic markers (P < .0001). Hazard ratios for death in these 4 groups after adjusting for International Prognostic Index and age were 1.0 (reference group), 0.58, 8.63, and 4.16, respectively (P = 7.10 × 10(-5)). These results were similar when restricted to patients receiving anthracycline-based chemotherapy, as well as to patients not receiving stem cell transplantation. Thus, ALK-negative ALCL is a genetically heterogeneous disease with widely disparate outcomes following standard therapy. DUSP22 and TP63 rearrangements may serve as predictive biomarkers to help guide patient management.

Histopathological characterization of a Cameron lesion.

Cameron lesions are linear erosions located at the neck of a hiatal hernia (HH) in patients with a large HH. The prevalence has been seen in up to 5% of patients with HH who undergo esophagogastroduodenoscopy, and they can be associated with overt gastrointestinal bleeding or anemia. These lesions occur due to vascular compression by the diaphragm in a large sliding HH. Histopathologic changes seen in the biopsy tissue of a Cameron lesion are due to ischemia, but this ischemia is reversible with treatment of HH. The existence of this entity and the histopathologic picture of a Cameron lesion is not well known to pathologists, and therefore, a microscopic picture of a Cameron lesion can be easily confused with ischemic gastritis. Ischemic gastritis is the result of atherosclerosis, usually seen in older people, unrelated to HH, and is not easily reversible. The authors received a gastric biopsy of a hiatal hernia without any associated clinical diagnosis of a Cameron lesion conveyed to the pathologist. This biopsy tissue showed ischemic changes in the gastric mucosa on microscopic examination. Diagnosis of ischemic gastritis was considered but ruled out after the case was discussed with the gastroenterologist. The correct diagnosis was made once the clinical diagnosis of HH with Cameron lesion (ie, a vertical red erosion) was made known to the pathologist. By reporting this case, the authors aim to increase awareness of Cameron lesion among pathologists so that they ask about the presence of a Cameron lesion before making the diagnosis of ischemic gastritis.

Co-occurrence of Langerhans cell histiocytosis and Rosai-Dorfman disease: possible relationship of two histiocytic disorders in rare cases.

Rosai-Dorfman disease and Langerhans cell histiocytosis are both disorders of accessory immune cells. Two cases have been previously reported of concurrent Langerhans cell histiocytosis and Rosai-Dorfman disease. In this report, we characterize the findings and selected molecular studies in nine additional cases. Histology was reviewed. Immunohistochemical stains were performed on all cases in which slides or blocks were available. A combination of CD1a, S-100, CD3, CD20, langerin, CD68, CD163, CD21, CD35 and CD123 immunohistochemical stains were performed. High-resolution array comparative genomic hybridization was performed on six samples from five cases. In these cases, seven were female and two male, with an average age of 25 years (15 months-59 years). A majority of the cases were identified in lymph node. Areas of Langerhans cell histiocytosis had a typical appearance with the existence of bland 'coffee-bean' nuclei, clear cytoplasm and associated eosinophils. The immunophenotype was typical, including expression of CD1a, S100, CD68 and langerin. In areas of Rosai-Dorfman disease, there was emperipolesis seen in all cases. Cells were intermediate-large in size with large round nuclei and ample clear or pale cytoplasm. The lesional cells were positive for S100, CD68, CD163, without expression of langerin or CD1a. Array comparative genomic hybridization showed gains and/or losses in four of the six samples. One case showed no gains or losses and one additional case showed gains and losses in the Langerhans cell histiocytosis, while no abnormalities were discovered in the Rosai-Dorfman disease component. These findings are comparable to those seen in previous studies of Langerhans cell histiocytosis. We report the clinical and pathologic findings of the combination of Langerhans cell histiocytosis and Rosai-Dorfman disease. Furthermore, we suggest on the basis of evidence from our cases that, when simultaneous, the two entities may be pathophysiologically related.

Fuzeon-induced collagenophagic granuloma: a peculiar granulomatous injection site reaction to Fuzeon--a case report and review of literature.

Enfuvirtide (ENF, T-20, or Fuzeon [Hoffman-La Roche Inc, Nutley, NJ, and Trimeris, Inc, Durham, NC]) is an HIV-1 fusion inhibitor and is the only injectable antiretroviral drug available. Injection site reactions (ISRs) are the most frequently reported adverse events, occurring in about 98% of patients. A granuloma annulare-like granulomatous ISR has been reported. We report a granulomatous ISR that is different from granuloma annulare and granuloma annulare-like reaction because it is rich in multinucleated giant cells engulfing altered collagen. We call this type of ISR a collagenophagic granuloma. Most previous reports-with the exception of 1 report-about ISRs with ENF treatment have used punch biopsies, which lack the depth to analyze the reticular dermis and subcutaneous tissue and, therefore, may have missed ISRs, which look like granuloma annulare, and the collagenophagic granulomatous reaction.