BackgroundWe report a case of sarcoidosis in a patient with metastatic melanoma managed with combination ipilimumab/nivolumab. Sarcoid development has been linked with single agent immunotherapy but, to our knowledge, it has not been reported with combination ipilimumab/nivolumab treatment. This case raises unique management challenges for both the melanoma and the immunotherapy-related toxicity.Case presentationA 46 year old Caucasian female with M1c-metastatic melanoma was managed with ipilimumab/nivolumab combination. Patient experienced response in baseline lesions but developed new clinical and radiographic findings. Biopsy of new lesions at two different sites both demonstrated tumefactive sarcoidosis. Staining of the biopsy tissue for PD-L1 expression demonstrated strong PD-L1 staining of the histiocytes and lymphocytes within the granulomas. Monotherapy nivolumab was continued without progression of sarcoid findings or clinical deterioration.ConclusionsTissue biopsy for evaluation of new lesions on immunotherapy is an important step to help guide decision making, as non-melanoma lesions can mimic disease progression.

Introduction Optimal approaches to induce T-cell infiltration of tumors are not known. Chemokines CXCL9, CXCL10, and CXCL11 support effector T-cell recruitment, and may be induced by IFNγ. This study tests the hypothesis that intratumoral administration of IFNγ will induce CXCL9-11, and will induce T-cell recruitment and anti-tumor immune signatures in melanoma metastases. Patients and Methods Nine eligible patients were immunized with a vaccine comprised of 12 class I MHC-restricted melanoma peptides and received IFNγ intratumorally. Effects on the tumor microenvironment were evaluated in sequential tumor biopsies. Adverse events (AEs) were recorded. T-cell responses to vaccination were assessed in PBMC by IFNγ ELIspot assay. Tumor biopsies were evaluated for immune cell infiltration, chemokine protein expression and gene expression. Results Vaccination and intratumoral administration of IFNγ were well tolerated. Circulating T-cell responses to vaccine were detected in 6 of 9 patients. IFNγ increased production of chemokines CXCL10, CXCL11, and CCL5 in patient tumors. Neither vaccination alone nor the addition of IFNγ promoted immune cell infiltration or induced anti-tumor immune gene signatures. Conclusion The melanoma vaccine induced circulating T-cell responses, but they failed to infiltrate metastases, thus highlighting the need for combination strategies to support T-cell infiltration. A single intratumoral injection of IFNγ induced T-cell attracting chemokines; however, it also induced secondary immune regulation that may paradoxically limit immune infiltration and effector functions. Alternate dosing strategies or additional combinatorial treatments may be needed to promote trafficking and retention of tumor-reactive T-cells in melanoma metastases.

Desmoplastic melanomas (DM) have unique and challenging clinical presentations and histomorphology. A characteristic feature is the presence of scattered lymphoid aggregates. However, the nature of these aggregates is not defined. We hypothesized that they may be tertiary lymphoid structures (TLS), and may be associated with programmed death ligand 1 (PD-L1) expression. We searched our tissue database for 'pure' DMs and for scars as control tissues, collected clinical information, and reviewed H&E histology. We performed multispectral imaging after staining for CD8, CD20, PNAd, FoxP3, CD83, and Ki67, and assessed PD-L1 expression by immunohistochemistry. Pure DM samples were evaluable in 11 patients. All had desmoplastic stroma and lymphoid aggregates on H&E. The lymphoid aggregates of eight of the 11 (72%) DM samples and only three of the 11 scars contained features of TLS, defined as distinct clusters of B cells and CD8 T cells, CD83 dendritic cells in T-cell zones, and PNAd vasculature resembling high endothelial venules. PD-L1 was expressed by at least 1% of melanoma cells in six and by at least 5% of immune cells in 10 of the 11 DM samples. We found that most lymphoid aggregates in DM are organized, classical TLS. PD-L1 expression was detected in most cases and was highest in two cases of DM with TLS. However, low PD-L1 expression in some cases suggests that some DM cells may be unresponsive to interferon-γ. TLS support antigen presentation and T-cell responses in chronic inflammation and cancer. Their presence in DM likely reflects an adaptive immune response, which may be enhanced with immune therapies.

Introduction Infiltration of cancers by T-cells is associated with improved patient survival and response to immune therapies; however, optimal approaches to induce T-cell infiltration of tumors are not known. This study was designed to assess whether topical treatment of melanoma metastases with the TLR7 agonist imiquimod plus administration of a multipeptide cancer vaccine will improve immune cell infiltration of melanoma metastases. Patients and Methods Eligible patients were immunized with a vaccine comprised of 12 melanoma peptides (12MP) and a tetanus toxoid-derived helper peptide, and imiquimod was applied topically to metastatic tumors daily. Adverse events were recorded and effects on the tumor microenvironment (TME) were evaluated from sequential tumor biopsies. T-cell responses were assessed by IFNγ ELIspot assay and T-cell tetramer staining. Patient tumors were evaluated for immune cell infiltration, cytokine and chemokine production, and gene expression. Results and Conclusions Four eligible patients were enrolled, and administration of imiquimod and vaccination were well-tolerated. Circulating T-cell responses to the vaccine were detected by ex vivo ELIspot assay in 3 of 4 patients. Treatment of metastases with imiquimod induced immune cell infiltration and favorable gene signatures in the patients with circulating T-cell responses. This study supports further study of topical imiquimod combined with vaccines or other immune therapies for the treatment of melanoma.

We report a series of four cases of individual patients with coexisting diagnoses of some combination of MF, LyP, and pcALCL, whose lesions presented in nontraditional sequence and demonstrated a retained clone by gene rearrangement analysis.

Sentinel lymph node biopsy (SLNB) is performed for some thin melanomas in the presence of concerning histopathological features. There are no defined standards for how sentinel nodes should be processed to detect microscopic metastases. We compared our method of serially sectioning nodes at 2-3 mm intervals and performing one hematoxylin and eosin (H&E) slide versus multiple H&E levels and utilizing immunohistochemistry (IHC). This was a retrospective review of a prospectively collected database identified patients with thin melanomas treated with wide local excision and SLNB between 1995 and 2010. Two patients had positive nodes. Out of 95 patients with negative SLNBs, 48 (49 nodes) patients were evaluable. Additional sections of each SLNB tissue block were stained with H&E (×2), Melan-A (×2) and HMB45 (×2), and reviewed by two pathologists. Additional histopathological sections showed that 1/49 (2.0%) nodes originally called negative had evidence of metastasis, which was evident both on additional H&E levels and by IHC; 3/49 (6.1%) nodes had benign nodal rests. All other nodes (45/49, 91.8%) were negative by H&E and IHC for metastatic disease. This study supports previous work suggesting the value of IHC in detecting micrometastases in melanoma sentinel nodes. Especially for thin melanomas where metastases are uncommon, but where detection of the metastasis upstages considerably from stage IA to IIIA, evaluation of nodes may be enhanced by combining breadloafing at 2-3 mm intervals with multiple H&E sections and IHC analysis.

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Intranodal spindle cell lesions on biopsy are problematic for a surgical pathologist, often requiring an extensive immunohistochemical evaluation with variable and frequently unsatisfactory results. In the absence of a history of malignancy, the differential diagnosis of a spindle cell tumor must include both a primary nodal proliferation and a metastatic process. Particularly challenging are those lesions that share morphologic and immunohistochemical features; spindle cell melanomas (SCM) and interdigitating dendritic cell sarcomas (IDCS) belong to this category. At present, electron microscopy is the only method proposed to distinguish between the 2 entities; however, this method is often unavailable and impractical. In this study, we assessed the comparative immunophenotypes of 18 cases of SCM and 8 cases of IDCS, with particular emphasis on the expression of MUM-1, β-catenin, SOX-10, MiTF, and p75. Our results showed nearly equivalent staining patterns and profiles; 12% and 17% of IDCS and SCM were labeled for MUM-1, 75% and 83% stained for β-catenin, 0% and 24% expressed MiTF, and 100% and 94% labeled for p75, respectively. All cases of IDCS and SCM displayed strong nuclear reactivity for SOX-10. On the basis of our study and pertinent literature, the morphologic and immmunophenotypic features of SCM and IDCS appear to be virtually indistinguishable from one another, raising the question as to whether these 2 entities represent a pathobiologically similar or even identical process.