Desmoplastic melanoma: Demographic and clinicopathological features and disease-specific prognostic factors

Joinpoint regression analysis of recent trends in desmoplastic malignant melanoma incidence and mortality: 15-year multicentre retrospective study

BACKGROUND

Recent data reveal a marked rise in the detection and mortality rates of Desmoplastic Malignant Melanoma (DMM). This trend underscores the imperative for an in-depth analysis of DMM's epidemiology, which is crucial for the formulation of precise medical and public health strategies. This investigation seeks to elucidate the variations in the incidence and mortality of DMM over a 15-year period (2005-2019).

METHODS

Data on DMM patients was sourced from the Surveillance, Epidemiology, and End Results (SEER) database. Both incidence and incidence-based mortality rates (IBM) were directly extracted from the SEER database. Joinpoint regression was used to analyze and calculate the average annual percent change (AAPC) and its 95% confidence interval (CI).

RESULTS

Between 2005 and 2019, 3,384 DMM cases were identified, boasting an age-adjusted incidence rate of 36.3 cases per 1000,000 person-years (95% CI 3.51-3.76) and an IBM of 1.65cases per 1000,000 person-years (95% CI 1.57-1.74). Of these, 2,353 were males (69.53%) and 1,031 were females (30.47%). There were 1894 patients (55.97%) who were over 70 years old. Predominantly, DMM lesions manifested in exposed areas: Limbs (955, 28.22%), Face (906, 26.77%), and Scalp and Neck (865, 25.56%). The incidence of DMM increased significantly at a rate of APC = 0.9% during 2005-2019, while the incidence-based mortality showed a significant upward trend (APC = 7%) during 2005-2012, and slowly increasing trend (APC = 0.6%) during 2012-2019. In contrast to the modest upward trajectory in female incidence and mortality, male incidence initially surged, later declining, while male mortality peaked and stabilized post-2012. The primary sites for incidence and mortality were chronically sun-exposed areas: Face, Scalp and Neck, and Limbs.

CONCLUSIONS

In recent years, the incidence and incidence-based mortality of DMM have significantly increased. Each subgroup analysis has different trends, and these trends can provide better support for our exploration of DMM.

Desmoplastic Melanoma: A Clinicopathological Analysis of Three Cases in the Chinese Population

Purpose

To investigate the clinicopathological characteristics and immunophenotype of desmoplastic melanoma (DM) in the Chinese population.

Patients and Methods

We report three cases of DM diagnosed by the Pathology Department of Shanghai Dermatology Hospital. We describe the clinical and pathological characteristics of the three cases and examine molecular markers used in the diagnosis of DM. Finally, we summarize the current literature in the DM field.

Results

Clinically, lesions in the three DM patients were characterized by non-pigmented nodules or papules. Microscopically, we observed an abundance of fibrous interstitium mixed with spindle cells exhibiting various degrees of atypia. Occasionally, these structures exhibited changes in lentigo maligna at the epidermal junction, accompanied by the presence of lymphoid follicular structures and neurophilic behavior. Diagnosis of DM was confirmed by immunohistochemical staining, which revealed high expression levels of S-100 and SOX-10. Melanocyte markers were focally positive or negative. Unlike DMs from other populations, our three patients were negative for WT-1 and P53. All three cases received surgical resection, which is the preferred treatment for DM, and none of the patients experienced recurrence.

Conclusion

DM in these Chinese patients was similar to that observed in other DM populations in terms of immunophenotype and clinical and histological features. A notable absence in p53 staining was observed in the three cases reported here, suggesting that p53 negativity should not exclude the diagnosis of DM in the Chinese population.

Development and validation of prognostic nomogram in patients with nonmetastatic malignant melanoma: a SEER population-based study

BACKGROUND

The condition of tumor recurrence and overall death can be worried in the progress of nonmetastatic malignant melanoma (NMMM). Our goal was to construct and validate a prognostic nomogram from a large population database, which is vital for physicians to predict the 3- and 5-year overall survival (OS) rates of patients with NMMM.

METHODS

According to the Surveillance, Epidemiology, and End Results (SEER) program, patients were collected and randomly assigned into the training and validation cohorts. Several independent risk factors were identified based on the methods of univariable and multivariable cox hazards regression and were incorporated to develop a nomogram. The concordance index (C-index), the area under the receiver operating characteristics (AUC) curve and calibration plot were confirmed to assess predictive power of the nomogram. Decision curve analysis (DCA) was performed to measure nomogram for the clinical practice.

RESULTS

A total of 66192 eligible patients, randomly assigned into 70% of training (n = 46 336) and 30% of validation cohorts (n = 19 856), were selected in this study. The selected independent factors were applied to develop a nomogram, and validated indexes indicated nomogram had a good discrimination ability. The C-index for OS rates was 0.817 (95% CI: 0.811-0.823) in training cohort and 0.817 (95% CI: 0.809-0.825) in validation cohort, respectively. The AUCs of 3- and 5-year OS rates were more than 0.79, and the calibration plots also showed a good power for the nomogram. DCA demonstrated that constructed nomogram can provide clinical net benefit.

CONCLUSION

We constructed a novel nomogram that more accurately and comprehensively predict OS with nonmetastatic malignant melanoma patients, which is vital for clinician to improve individual treatment, make reasonable clinical decisions, and set appropriate follow-up strategies.