Hodgkin lymphoma (HL) is a disease of young adults (12% of all lymphomas) and elderly people, and is composed of two separate entities: classical HL (95% of cases) and nodular lymphocytic predominant HL (5% of cases)
. First described by the German physician Grosz in 1906, cutaneous Hodgkin lymphoma (CHL), an exceedingly rare manifestation of the disease (0.5 – 7.5 %), occurs when the malignant cells invade the dermis
. Nonetheless, cutaneous symptoms can be seen in up to 40% of patients with HL
. The current WHO-EORTC classification identifies cutaneous HL as a secondary systemic dissemination of the disease
[1, 4]. Cutaneous manifestation of HL show different clinical features: (a) papules, (b) plaques, (c) nodules or tumors, (d) ulcerative lesions, (e) various combinations of these features and (f) erythroderma
. It is usually centered in the reticular dermis and commonly extends into the subcutaneous fat. The tumor shows nodular or interstitial growth pattern with adnexal involvement. Various forms of Reed- Sternberg cells with large, hyperchromatic, irregular shaped nuclei are easily identifiable. The Reed-Sternberg cells are admixed predominantly with plasma cells and lymphocytes with occasional histiocytes and eosinophils. Necrosis is generally absent. The epidermis is spared in most of the cases
[2–5]. In this particular case, the patient had a remote history of nodular sclerosis classical Hodgkin lymphoma that preceded the secondary involvement of the skin by many years (10–15 years). Although his original biopsy slides were not available for review, the histologic features seen on the diagnostic skin biopsy were more suggestive of a mixed cellularity variant of CHL: there was an abundance of mixed inflammatory cells that included neutrophils, histiocytes, plasma cells, lymphocytes, and rare eosinophils without significant fibrosis. The population of RS cells and variants was significant as it is depicted on the Figure
Based on morphology alone, it is almost impossible to distinguish CHL with abundant numbers of neoplastic cells from other primary cutaneous lymphoproliferative disorders, such as CD30+ lymphoproliferative disorder (lymphomatoid papulosis (LyP) and primary cutaneous anaplastic large-cell lymphoma (ALCL)), or even tumor stage mycosis fungoides when the epidermotropism is minimal. Other reactive CD30+ processes including: pseudolymphomatous drug reactions, nodular scabies, atopic dermatitis, and infections can also be in the differential diagnosis
By immunohistochemistry, the neoplastic cells in Classical HL are positive for CD30 in nearly all cases and CD15 for the majority (75–85%) of cases and are usually negative for CD45, CD20, ALK and EMA. However, up to 20-30% of CHL can be positive for CD20, and its positivity is a marker of better prognosis, and response to rituximab. The B-cell nature of Reed-Sternberg cells is shown by the B-cell specific activator protein (BSAP), product of the PAX-5 gene in approximately 90% of cases. Additionally the tumor cells can be positive for EBER, by in-situ hybridization
[1, 5, 6]. Other immunohistochemical markers that have some utility are OCT-2 and BOB-1, which are positive (not both) in up to 90% of cases
. In contrast, LyP, c-ALCL, or transformed MF show invariable negative expression of CD15 or Pax-5
[4, 6]. A systemic B-cell lymphoma that can sometimes enter in the differential diagnosis is T-cell histiocyte-rich large B-cell lymphoma (THRLBCL). But in THCRLBCL there is strong expression of CD45, CD20, CD79a and PAX-5. The current case showed a typical CHL immunophenotype with CD30 and CD15 expression, but negative for CD45. An unusual phenotype with CD20 and CD79a expression was also seen, but PAX5 showed the classic dim staining characteristic of CHL. EBER was negative, a feature commonly seen in most cases of nodular sclerosis and mixed cellularity CHL.
The mode of HL spread to the skin has been explained by three mechanisms: (1)retrograde lymphatic spread, distal to the tumor involved regional lymph node(s), which is the most common; (2)direct extension from an underlying nodal focus; and (3) hematogenous dissemination where no tumor-involved lymph nodes are identified in the immediate vicinity of the involved skin
The coexistence of different malignancies in patients with Hodgkin and NHL has been previously documented: Yang et al.
 reported a patient with nodal angioimmunoblastic T-cell lymphoma (AITCL) who had a partial response to chemotherapy, and developed an EBV-associated cutaneous diffuse large B-cell lymphoma few months after his original diagnosis of AITCL. El Demellawy et al.
 reported a synchronous collision tumor of malignant melanoma and chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). We have also seen in our personal experience the coexistence of CLL/SLL with melanoma and squamous cell carcinoma.
Concurrent malignant melanoma and lymphoma occurs in 0.3% of patients with melanoma
. Since 1960, a rising incidence of melanoma and NHL has been observed, probably related to UV exposure and immunosupression (such as cases presenting in individuals who are stem cell transplant recipients and patients with AIDS)
[9, 10]. Adami et al.
 first reported a link between NHL, CLL/SLL and skin cancer (the relative risk of developing melanoma was 2.4 among NHL patients) and suggested that UV light may contribute to increasing incidence of NHL. Riou et al.
 reported a 16 fold higher incidence of lymphomas in patients with malignant melanoma. A recent study also found a 3.5 to 7.5 fold increase of NHL in patients with melanoma
. Alterations of p16 pathway, which inhibit CDNK4, a tumor suppressor gene, are common in both types of malignancies
More interestingly, the development of skin cancers after non-myeloablative allogeneic bone marrow transplants (NMAT) has been well documented. Cavalier et al.
 reported a series of 6 cases of skin cancers (mostly squamous cell carcinomas, but 2 of the patients had melanoma) in patients with NMAT. The most interesting finding in their study was a particular strong association of skin cancers in those patients who received their transplant for myelodysplasia or acute myeloid leukemia. In this case the patient developed a therepy related myeloid neoplasm subsequent to the chemotherapy for CHL. The mechanism implicated in the development of skin cancers is the immunosupression from the induction chemotherapeutic regimens that are administered prior to the transplant. In particular, the depletion of CD4+ lymphocytes is a well known predisposer for skin cancers. Patients who have an aggressive myeloid neoplasm usually receive more intensive induction regimens, a fact that creates a more immunosuppressive background. Ultimately, fludarabine, a purine analogue that is typically use in induction chemotherapy, results in DNA inactivation and apoptosis. Fludarabine also inhibits DNA-polymerase, RNA-polymerase, DNA-ligase, DNA-primase and ribonucleotide reductase
. Fludarabine also depletes CD3, CD4 and CD8 lymphocytes over a period of a month. In this case fludarabine was one of the drugs administered prior to his transplant. Additional possible mechanisms which are linked to carcinogenesis include p53 mutations and HPV infection (in squamous cell carcinomas).
In the past, 3 cases of patients with melanoma developed Hodgkin’s disease thereafter and were published in the literature
[7, 9]. However, concurrent cutaneous involvement by HL and melanoma has never been reported. Causality between both malignancies remains to be established. Our case illustrates the first case report of malignant melanoma and CHL in a patient presenting simultaneously.
An attempt to obtain informed consent was performed. However, this patient has been lost to follow up, and no close family members were available (based on the provided demographic information) to obtain informed consent from.