[Cytarabine and hematopoietic cell transplantation for mantle cell lymphoma. Analysis of 20 patients]. / Resultados de pacientes con linfoma del manto: impacto de terapias basadas en citarabina y trasplante hematopoyético.

BACKGROUND: Mantle cell lymphoma (MCL) has high relapse and mortality rates. There is a survival benefit when treatment is intensified with cytarabine (AraC), hematopoietic cell transplantation (HCT) and maintenance with rituximab. AIM: To assess the outcomes of patients with MCL treated in a university hospital. MATERIAL AND METHODS: Review of an oncology center database and medical records identifying patients with MCL treated between 2006 and 2017. Death dates were obtained from the death certificate database of the National Identification Service. We analyzed the response rate, overall survival (OS) and progression-free survival (PFS). As a secondary objective, the survival impact of AraC, HCT and maintenance with rituximab, was also analyzed. RESULTS: Information on 20 patients aged 62 ± 11 years, followed for a median of 45 months was retrieved. Eighty-five percent were diagnosed at an advanced stage. The most used first-line regime was R-CHOP in 11 patients, followed by R-HyperCVAD in five. Only 47% achieved complete response. 4-year PFS and OS were of 30 and 77% respectively. Mantle Cell Lymphoma International Prognostic Index (MIPI) significantly predicted PFS and OS. Maintenance with rituximab or HCT was associated with better PFS (48 vs 21 months, p < 0.01). The exposure to AraC or HCT, in refractory or relapsed disease, was associated with an increase in PFS from 9 to 28 months (p = 0,02) and 4-year OS from 40 to 100% (p = 0.05). OS increased even more, from 25 to 100% in those with high-risk MIPI (p = 0.04). CONCLUSIONS: The incorporation of AraC, HCT and maintenance with rituximab in the therapeutic backbone of MCL, especially for high-risk cases, was associated with improved survival.

Lymphadenectomy Specimens in a Large Retrospective Cohort of Pediatric Patients Reveal No in situ Lymphomas but a Broad Spectrum of Reactive Changes.

OBJECTIVES: While the incidence and prevalence of in situ follicular neoplasia (ISFN) and in situ mantle cell neoplasia (ISMCN) in adults are well documented, little is known about these early (precursor) lesions in pediatric populations. The aim of this study was to analyze so-called 'reactive' lymph nodes harvested for the purpose of staging solid tumors, unexplained lymphadenopathies, or presumed inflammatory processes or in conjunction with other surgical interventions in children and adolescents aged <18 years, with special attention to ISFN and ISMCN. METHODS: Formalin-fixed, paraffin-embedded reactive lymph node samples from an unselected pediatric population from two catchment areas in Switzerland were retrospectively analyzed for the presence of ISFN and ISMCN and specific reactive lymph node patterns. RESULTS: While a diverse range of histopathological patterns of reactive lymph node changes with a particular periodic increase in mycobacterioses could be observed in this pediatric population, not a single case of ISFN or ISMCN was found. CONCLUSIONS: Early histological lymphomagenesis equivalents in the form of in situ lymphomas are exceedingly rare events in children and young adolescents. The spectrum of reactive lymph node changes is large, with differences possibly determined by regional variations in geography, demographics, catchment areas, seasons, and years, respectively.

Case Study: Rare Case of Mantle Cell Lymphoma With Extranodal Involvement in the Foot.

Mantle cell lymphoma (MCL) is a rare type of non-Hodgkin lymphoma that commonly affects extranodal sites. The most commonly affected sites are the bone marrow, gastrointestinal tract, Waldeyer's ring, lung, and pleura. We report the case of an 80-year-old diabetic male, in MCL remission, who presented with a small dome-shaped nodule on his calf and an ipsilateral second digit non-healing ulceration after a traumatic fall. Despite surgical and conservative treatment, the wound worsened, resulting in histopathologic examination, which confirmed the presence of lymphocytes, indicating MCL relapse. This case was followed up for approximately 3 months until the patient died. Our case is an example of pedal manifestations of skin involvement of MCL, which, on consideration of the clinical manifestations also, can be confused with a nonhealing diabetic wound. The clinical significance of our case study is to assist in the diagnosis, management, and prognosis of a patient with MCL.

[Synchronous colorectal carcinoma and non-Hodgkin lymphoma - two case reports]. / Synchronní kolorektální karcinom a nehodgkinský lymfom - popis dvou prípadu.

Colorectal carcinoma represents an important cause of morbidity and mortality in adults, and its incidence in the Czech Republic is one of the world´s highest. The basic therapeutic approach is surgery: surgical removal of the affected part of the bowel together with regional lymph nodes dissection. The lymph nodes are routinely examined by means of histopathology. In this paper, we present two patients whose histological examination of mesocolic lymph nodes revealed an infiltration by synchronous malignant B-non-Hodgkin-lymphoma. Mantle cell lymphoma was present in the first case, and small cell lymphoma CLL/SLL in the other. Relevant literature is reviewed. KEY WORDS: synchronous - malignancy - colorectal - lymphoma - lymph node.

CHOP and DHAP plus rituximab followed by autologous stem cell transplantation in mantle cell lymphoma: a phase 2 study from the Groupe d'Etude des Lymphomes de l'Adulte.

Treatment of mantle cell lymphoma (MCL) in younger patients remains a challenge. We report results of a phase 2 trial using cytarabine and rituximab as induction regimen before autologous stem cell transplantation. Patients younger than 66 years with stage 3 or 4 MCL were included. Treatment consisted of 3 courses of CHOP(21) with rituximab at the third one and 3 of R-DHAP. Responding patients were eligible for autologous stem cell transplantation with TAM6 or BEAM. Sixty patients were included. Median age was 57 years. Characteristics of patients were: BM involvement 85%, leukemic disease 48%, gastrointestinal involvement 52%, Performance Status > 16%, lactate dehydrogenase > 1N 38%, Mantle Cell Lymphoma International Prognostic Index (low 55%, intermediate 38%, high 13%). The overall response rate was 93% after (R)-CHOP and 95% after R-DHAP. Although uncommon after (R)-CHOP (12%), 57% of patients were in complete response after R-DHAP. With median follow-up of 67 months, median event-free survival is 83 months, and median overall survival is not reached. Five-year overall survival is 75%. Comparison with a previous study without rituximab shows improvement of outcome (median event-free survival, 51 vs 83 months). No toxic death or unexpected toxicities were observed. This study confirms that induction with rituximab and cytarabine-based regimens is safe and effective in MCL patients. This regimen is currently compared with R-CHOP(21) induction in a multicentric European protocol.

A case of mantle cell lymphoma presenting as IgG4-related dacryoadenitis and sialoadenitis, so-called Mikulicz's disease.

BACKGROUND: Mantle cell lymphoma (MCL) is a relatively uncommon type of non-Hodgkin lymphoma. It develops in the outer edge of a lymph node called the mantle zone. In contrast, IgG4-related dacryoadenitis and sialoadenitis (IgG4-DS) is characterized by elevated serum IgG4 and persistent bilateral enlargement of lacrimal glands (LGs) and salivary glands (SGs), with infiltration of IgG4-positive plasma cells. Recent studies indicated the importance of differentiation between IgG4-DS and malignant lymphoma. CASE PRESENTATION: An 82-year-old man was suspected of IgG4-DS because of a high serum IgG level (2174 mg/dL) and bilateral swelling of LGs and SGs. Lip biopsy and fine needle biopsy of submandibular gland were performed, and subsequently, MCL was diagnosed through the histopathological findings. CONCLUSIONS: MCL most commonly occurs in the Waldeyer ring, but rarely in the stomach, spleen, skin, LG, and SG. We report an unusual case of MCL involving LGs and SGs mimicking IgG4-DS, which suggests that IgG4 testing may be useful in the differentiation of IgG4-DS in the presence of bilateral swelling of LGs or SGs.

Prognostic role of SOX11 in a population-based cohort of mantle cell lymphoma.

The prognostic role of the transcription factor SOX11 in mantle cell lymphoma (MCL) is controversial. We investigated prognostic markers in a population-based cohort of 186 MCL cases. Seventeen patients (9%) did not require any therapy within the first 2 years after diagnosis and were retrospectively defined as having an indolent disease. As expected, indolent MCL had less frequent B symptoms and extensive nodal involvement and 88% of these cases expressed SOX11. In our cohort 13 cases (7.5%) lacked nuclear SOX11 at diagnosis. SOX11(-) MCL had a higher frequency of lymphocytosis, elevated level of lactate dehydrogenase (LDH), and p53 positivity. The overall survival in the whole cohort, excluding 37 patients receiving autologous stem cell transplantation, was 3.1 year and in patients with indolent or nonindolent disease, 5.9 and 2.8 years, respectively (P = .004). SOX11(-) cases had a shorter overall survival, compared with SOX11(+) cases, 1.5 and 3.2 years, respectively (P = .014). In multivariate analysis of overall survival, age > 65 (P = .001), Eastern Cooperative Oncology Group score ≥ 2 (P = .022), elevated LDH level (P = .001), and p53 expression (P = .001) remained significant, and SOX11 lost significance. We conclude that most indolent MCLs are SOX11(+) and that SOX11 cannot be used for predicting an indolent disease course.

Allogeneic stem cell transplantation for mantle cell lymphoma--final report from the prospective trials of the East German Study Group Haematology/Oncology (OSHO).

This study was conducted in order to evaluate allogeneic stem cell transplantation (alloSCT) as consolidation for patients with mantle cell lymphoma (MCL). Patients with MCL were included into two prospective trials OSHO #060 (refractory/relapsed) and #074 (de novo). Induction was rituximab and chemotherapy. Responding patients proceeded to alloSCT. Minimal residual disease was monitored by quantitative RT-PCR detecting either t(11;14) or clonospecific CDR-III regions. In case of circulating lymphoma cells, immunomodulation (cyclosporine A withdrawal, rituximab, donor lymphocyte infusion) was initiated. Thirty-three of 39 patients underwent alloSCT after myeloablative (n = 7) or toxicity-reduced (n = 26) conditioning. Leukocytes engrafted at day +16 (median, range 0-101) and platelets at day +14 (0-142). Acute graft-versus-host disease stages I-II occurred in 42 % and stages III-IV in 15 %. Five patients have relapsed after SCT. The overall mortality after SCT was 24 % (n = 8). Median follow-up after SCT was 2.8 years (range 0.0-10.9). Five-year progression-free survival was 67 %, and overall survival 73 % after SCT. The results were comparable for primary MCL and refractory/relapsed disease as well as for related vs. unrelated SCT. Younger patients had a significantly better outcome than the elderly. AlloSCT is a feasible and promising consolidation therapy for relapsed and refractory disease and an attractive option for young patients with de novo MCL of high risk.

Specific features identify patients with relapsed or refractory mantle cell lymphoma benefitting from autologous hematopoietic cell transplantation.

Outcomes with autologous hematopoietic cell transplantation (auto HCT) for relapsed and/or refractory mantle cell lymphoma (MCL) are typically poor. We hypothesized that certain factors could predict which patients experience a favorable outcome with this approach. We thus developed a predictive score from a cohort of 67 such patients using 3 factors independently associated with progression-free survival (PFS): (1) simplified Mantle Cell Lymphoma International Prognostic Index score before auto HCT (hazard ratio [HR], 2.9; P = .002); (2) B symptoms at diagnosis (HR, 2.7; P = .005); and (3) remission quotient, calculated by dividing the time, in months, from diagnosis to auto HCT by the number of prior treatments (HR, 1.4; P = .02). The estimated 5-year PFS for favorable-risk patients (n = 23) and unfavorable-risk patients (n = 44) were 58% (95% confidence interval [CI], 34% to 75%) and 15% (95% CI, 6% to 28%), respectively. These factors also independently predicted overall survival. In summary, we have defined 3 simple factors that can identify patients with relapsed/refractory MCL who derive a durable benefit from salvage auto HCT.

Cytarabine, Ki-67, and SOX11 in patients with mantle cell lymphoma receiving rituximab-containing autologous stem cell transplantation during first remission.

BACKGROUND: In the current study, the authors report the results of 39 patients with mantle cell lymphoma (MCL) who were treated with chemotherapy and high-dose rituximab-containing autologous stem cell transplantation (ASCT) during their first disease remission. METHODS: The median age of the patients was 54 years. At the time of diagnosis, 87% of patients had Ann Arbor stage IV disease, and 77% had bone marrow involvement. A Ki-67 level of > 30% was found in 11 of 27 patients (40%), and SOX11 (SRY [sex determining region Y)-box 11] expression was found to be positive in 17 of 18 patients (94%). Twenty-seven patients (69%) underwent induction therapy with high-dose cytarabine-containing chemotherapy. Rituximab was administered during stem cell collection at a dose of 1000 mg/m2 on days +1 and +8 after ASCT. RESULTS: The estimated 4-year overall survival and progression-free survival rates were 82% and 59%, respectively. Twelve patients experienced disease recurrence. Fifteen of 16 patients who were alive and in complete remission at 36 months remained so at a median follow-up of 69 months (range, 38 months-145 months). The only determinant of recurrence risk found was a Ki-67 level of > 30%. Seven of 11 patients with a Ki-67 level > 30% experienced disease recurrence within the first 3 years versus only 3 of 16 patients with a Ki-67 level ≤ 30% (P = .02). Patients who received high-dose cytarabine did not have a significantly different risk of developing disease recurrence compared with other patients (P = .7). CONCLUSIONS: Administering ASCT with rituximab during stem cell collection and immediately after transplantation may induce a continuous long-term disease remission in patients with MCL with a Ki-67 level of ≤ 30%.

Mantle cell lymphoma: 2013 Update on diagnosis, risk-stratification, and clinical management.

DISEASE OVERVIEW: Mantle cell lymphoma (MCL) is a non-Hodgkin lymphoma characterized by involvement of the lymph nodes, spleen, blood, and bone marrow with a short remission duration to standard therapies and a median overall survival of 4-5 years. DIAGNOSIS: Diagnosis is based on lymph node, bone marrow, or tissue morphology of centrocytic lymphocytes, small cell type, or blastoid variant cells. A chromosomal translocation t(11:14) is the molecular hallmark of MCL, resulting in the overexpression of cyclin D1. Cyclin D1 is detected by immunohistochemistry in 98% of cases. The absence of SOX-11 or a low Ki-67 may correlate with a more indolent form of MCL. The differential diagnosis of MCL includes small lymphocytic lymphoma, marginal zone lymphoma, and follicular lymphoma. RISK STRATIFICATION: The Mantle Cell Lymphoma International Prognostic Index (MIPI) is the prognostic model most often used and incorporates ECOG performance status, age, leukocyte count, and lactic dehydrogenase. A modification of the MIPI also adds the Ki-67 proliferative index if available. The median overall survival (OS) for the low risk group was not reached (5-year OS of 60%). The median OS for the intermediate risk group was 51 months and 29 months for the high risk group. RISK-ADAPTED THERAPY: For selected indolent, low MIPI MCL patients, initial observation may be appropriate therapy. For younger patients with intermediate or high risk MIPI MCL, aggressive therapy with a cytarabine containing regimen ± autologous stem cell transplantation should be considered. For older MCL patients with intermediate or high risk MIPI, combination chemotherapy with R-CHOP, R-Bendamustine, or a clinical trial should be considered. At the time of relapse, agents directed at activated pathways in MCL cells such as bortezomib (NFkB inhibitor) or lenalidamide (anti-angiogenesis) are approved agents. Clinical trials with Ibruitinib (Bruton's Tyrosine Kinase inhibitor) or Idelalisib (PI3K inhibitor) have demonstrated excellent clinical activity in MCL patients. Autologous or allogeneic stem cell transplantation can also be considered in young patients.

The place of transplantation in mantle cell lymphoma.

Mantle cell lymphoma (MCL) is an uncommon non-Hodgkin lymphoma with a heterogeneous natural history. Significant strides have been made in the management of MCL. Clinical follow-up exceeds a decade with long-term remission durations in some patients. Modern induction strategies employ rituximab; a cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP)-like backbone; and cytarabine (in alternating or sequential regimens). However, bendamustine/rituximab therapy is challenging these induction strategies. The role of transplant is in clinical evolution. Up-front high-dose therapy and autologous stem cell transplant remains an attractive option for those with chemosensitive disease regardless of the induction regimen chosen, whereas this approach in the relapsed or refractory setting has not yielded long-term disease-free intervals. Reduced-intensity allogeneic stem cell transplant remains a viable option in those with relapsed or refractory MCL.

Current and emerging therapies in mantle cell lymphoma.

Mantle Cell Lymphoma, characterized by the t(11;14)(q13; q32) chromosomal translocation and cyclin D1 expression, remains one of the most challenging lymphoma subtypes to treat. Therapy can be divided into treatment modalities for younger, stem cell transplant (SCT)-eligible patients vs older, SCT-ineligible patients. For clinically fit patients younger than 60-65 years of age we recommend cytarabine-containing induction and conditioning regimens such as Rituximab (R)-CHOP alternating with R-DHAP followed by autologous SCT consolidation. Elderly patients benefit from R-bendamustine or R-CHOP with maintenance rituximab following induction therapy, especially after R-CHOP. While standard chemoimmunotherapy provides high overall response rates, the responses are not durable and sequential therapies are thus necessary. MCL is proving to be sensitive to novel therapies that may in the near future become useful adjuncts to standard regimens. For example, bortezomib, lenalidomide, and temsirolimus each have single-agent efficacy in relapsed and refractory disease. Several targeted agents are emerging that likewise may transform management of MCL. The B-cell receptor pathway appears to be critical in the pathogenesis of MCL, and novel agents such as ibrutinib and idelalisib that target this signaling pathway are highly active in relapsed and refractory MCL. Similarly, cell cycle inhibitors targeting cyclin dependent kinases as well as HDAC inhibitors have shown promise in early studies.

Diagnostic challenges of composite colorectal tumors of adenoma-mantle cell lymphoma type.

Composite intestinal tumors of adenoma-lymphoma type are rare. To our knowledge 1 tumor showing this association has been previously reported, the histologic diagnosis being made retrospectively. We report the case of an 80-year old male patient complaining for epigastric pain, rectorrhagia, diarrhea, and weight loss. At endoscopy, a rectal lesion (3 cm) of villous low-grade dysplasia adenoma type was detected. Due to persistence of symptoms, new gastro- and coloscopies were performed, the biopsies showing low-grade dysplasia adenomas (right colon, and rectum) and an abundant lymphoid infiltrate (gastroduodenal anastomosis, small intestine, sigmoid, right and left colon, transverse colon, and rectum) of mantle cell lymphoma type, the rectal polyp being composed of both tumor types. The muscularis mucosa was focally infiltrated by the lymphoma, the bulk of the lymphoma being submucosal. After the treatment of 8 mini-cyclophosphamide, hydroxydaunorubicin, oncovin, prednisone cures, lymphoma persisted. On endoscopic ultrasound examination, after the 6 cures of bendamustine following the cyclophosphamide, hydroxydaunorubicin, oncovin, prednisone treatment, the signal of the rectal villous lesion disappeared in the peripheral layers, including of the muscular layer, suggestive of an invasive lesion or persistence of lymphoma. Biopsies confirmed the persistence of the rectal adenoma with low and high-grade adenoma, without lymphoma. In conclusion, the biopsic diagnosis of composite intestinal tumors of adenoma-mantle cell lymphoma type may be challenging, the bulk of the lymphoma being submucosal as in the present case. Although the malignant tumor treatment is the priority in such cases, the effects of chemotherapy on the evolution of benign tumors such as adenomas should be carefully assessed.

Reduced-intensity conditioning allogeneic stem cell transplantation for relapsed/refractory mantle cell lymphoma: a multicenter experience.

BACKGROUND: Despite therapeutic approach that combines rituximab-containing chemotherapy, followed or not by autologous stem cell transplantation (auto-SCT), mantle cell lymphoma (MCL) patients experience relapses. Reduced-intensity conditioning allogeneic stem cell transplantation (RIC-allo-SCT) at time of relapse may represent an attractive strategy. PATIENTS AND METHODS: We report a multicenter retrospective analysis. Seventy MCL patients underwent RIC-allo-SCT in 12 centers. RESULTS: Median age at transplantation was 56 years and median time from diagnosis to transplantation was 44 months. The median number of previous therapies was 2 (range, 1-5) including autologous transplantation in 47 cases. At time of transplantation, 35 patients were in complete remission, 20 were in partial response and 15 in stable disease or progressive disease. The median follow-up for living patients was 24 months. The 2-year event-free survival (EFS) and overall survival (OS) rates were 50% and 53%, respectively. The 1- and 2-year transplant-related mortality rates were 22% and 32%, respectively. The statistical analysis demonstrated that disease status at transplantation was the only parameter influencing EFS and OS. CONCLUSIONS: These results suggest that RIC-allo-SCT may be an effective therapy in MCL patients with a chemo-sensitive disease at time of transplantation, irrespective of the number of lines of prior therapy. Studies are warranted to investigate the best type of RIC regimen.

Autologous stem-cell transplantation in patients with mantle cell lymphoma beyond 65 years of age: a study from the European Group for Blood and Marrow Transplantation (EBMT).

BACKGROUND: Limited experience is available on the feasibility and efficacy of autologous stem-cell transplantation (ASCT) in patients with mantle cell lymphoma (MCL) beyond 65 years. DESIGN AND METHODS: We analysed 712 patients with MCL treated with ASCT from 2000 to 2007 and reported to the European Group for Blood and Marrow Transplantation registry. Patients>65 years were compared with patients<65 years for the end points non-relapse mortality (NRM), relapse incidence, progression-free survival (PFS), and overall survival (OS). RESULTS: Seventy-nine patients were ≥65 years old. Median time from diagnosis to ASCT was longer in the elderly patients (11 versus 9 months, P=0.005); they had more commonly received at least two treatment lines (62.0% versus 47.9%, P=0.02) and were less commonly in first complete remission at ASCT (35.4% versus 51.2%, P=0.002). Median follow-up after ASCT was 19 and 25 months, respectively. NRM was comparable at 3 months (3.8% versus 2.5%) and at 5 years (5.6% versus 5.0%). There were no differences in relapse rate (66% versus 55% at 5 years), PFS (29% versus 40%) and OS (61% versus 67%) between both populations of patients. CONCLUSION: ASCT beyond 65 years of age is feasible in selected patients with MCL and results in similar disease control and survival as in younger patients.

Human Herpesvirus-6 cytopathic inclusions: an exceptional and recognizable finding on skin biopsy during HHV6 reactivation after autologous stem-cell transplantation.

Skin rash are common in immunocompromised patients, particularly after bone marrow transplantation. Human herpes virus 6 (HHV6) reactivation is often suspected, but its clinical presentation and the routine laboratory tests may be unspecific, thus leading to late diagnosis. In this case, we report specific intralymphocytic cytopathic inclusions on skin biopsy as a sign of systemic HHV6 reactivation. A 56-year-old patient presented progressive erythroderma and fever occurring after autologous hematopoietic stem-cell transplantation for mantle cell lymphoma. The skin biopsy showed a perivascular infiltrate of medium-to-large lymphocytes with irregular nuclei containing a large central basophilic inclusion surrounded by a clear halo. High levels of HHV-6 genomic in skin biopsy confirm HHV-6-induced cytopathic effect. The clinical course improved with intravenous foscavir. The specific histopathological findings encountered in this case are exceptional but recognizable, and along with HHV-6 DNA detection allow a prompt recognition of HHV6 skin rash.

Lymphomatoid hypersensitivity reaction to levofloxacin during autologous stem cell transplantation: a potential diagnostic pitfall in patients treated for lymphoma or leukemia.

Drug-associated cutaneous lymphomatoid hypersensitivity reactions are rare eruptions that can clinically and microscopically mimic a bona fide lymphomatous process. Clinically, the appearance ranges from papulosquamous to purpuric. Histopathologically, these reactions simulate a wide variety of lymphoma subtypes; the most frequently reported examples resemble mycosis fungoides. We report a 61-year-old female who developed a purpuric eruption prior to engraftment of an autologous hematopoietic stem cell transplant for stage IV mantle cell lymphoma. Skin biopsies showed a superficial perivascular and interstitial infiltrate of large, immature-appearing mononuclear cells associated with spongiosis, papillary dermal edema and erythrocyte extravasation. The cells were immunoreactive for T-cell markers and lacked B-cell marker expression, excluding recurrence of the underlying mantle cell lymphoma as a diagnostic possibility. The cutaneous eruption was temporally linked to levofloxacin administration and resolved after discontinuation of this medication. This is the first report of a lymphomatoid hypersensitivity reaction associated with fluoroquinolone use. The histopathologic features presented in this paper underscore the potential for misdiagnosis of such lesions as lymphoma or acute myeloid leukemia, particularly in the setting of hematopoietic stem cell transplantation for underlying lymphoma or leukemia. Clinical correlation, morphologic comparison to the original malignancy and immunohistochemical studies aid the dermatopathologist in rendering the correct diagnosis.