Pigmented squamous cell carcinoma of the nail bed presenting as a melanonychia striata: diagnosis by perioperative reflectance confocal microscopy

Squamous cell carcinoma of the nail in patients with Fitzpatrick phototypes IV-VI: a systematic review

Squamous cell carcinoma of the nail unit (nSCC) is a rare malignant tumor of the hand and nail. Although skin cancer rarely affects individuals with phototypes IV-VI, its occurrence in these groups is often associated with greater morbidity and mortality. This study aims to characterize the clinical symptoms, presentations, and treatments of nSCC in patients with darker skin types. A systematic review of PubMed and Embase was performed in May 2023 for all peer-reviewed, English-language nSCC studies involving individuals with Fitzpatrick types IV-VI. Most tumors were located on the fingernails (84%), with the right third finger being the most frequently affected (31%). The nail bed (67%) exhibited a higher prevalence than the lateral/proximal nail folds (33%). The duration of symptoms before diagnosis ranged from 1 month to 7 years. nSCC was most commonly treated with Mohs surgery (38%), followed by amputation (35%). Our study was limited to case reports because of a lack of large nSCC studies that provide information on race or images of each patient. These tumors are generally slow-growing yet often misdiagnosed, leading to delays in presentation and diagnosis. Increased awareness about nSCC in phototype IV-VI individuals will reduce misdiagnoses, unnecessary treatment, and recurrences.

Ex vivo confocal microscopy: revolution in fast pathology in dermatology

Confocal microscopy with in vivo and ex vivo modalities has been used in the evaluation of skin cancer and other dermatological disorders. Recent developments in ex vivo confocal microscopy allow for faster pathology assessment with greater accuracy by the visualization of cellular and architectural details, similarly to standard pathology, in either paraffin-embedded or frozen samples. They include the possibility of multimodal confocal microscopy using different lasers and fusion images. New staining protocols including immunostaining, with no damage to conventional histopathology preparation, have been recently described in melanocytic tumours and inflammatory skin diseases. Digital staining with haematoxylin and eosin is also incorporated in the new devices. In this review the applications of ex vivo confocal microscopy will be presented with the description of the technique and the technology, clinical evidence in dermatology and other fields, and further applications.

Ex vivo confocal microscopy: an emerging technique in dermatology

This review aims to give an overview of the current available applications of ex vivo confocal microscopy (EVCM) in dermatology. EVCM is a relatively new imaging technique that allows microscopic examination of freshly excised unfixed tissue. It enables a rapid examination of the skin sample directly in the surgery room and thus represents an alternative to the intraoperative micrographic control of the surgical margins of cutaneous tumors by standard microscopic examination on cryopreserved sections during Mohs surgery. Although this technique has mainly been developed for the margin’s control of basal cell carcinoma, many other skin tumors have been studied, including melanoma. Use of EVCM is continuing to evolve, and many possible applications are under investigation, such as the study of nails and hair diseases and the diagnosis of skin infections.

Association of subungual melanoma and subungual squamous cell carcinoma: A case series

BACKGROUND

Subungual squamous cell carcinoma (SSCC) and subungual melanoma (SUM) are rare tumors. Several case reports of association of SSCC with SUM (SSCC-SUM) have been published.

OBJECTIVE

We sought to document the clinical, dermoscopic, and histologic features in a case series of SSCC-SUMs and describe their relative frequency compared with those of SSCC and SUM.

METHODS

All patients who underwent surgical exploration of the nail apparatus with a dermatopathologic examination from 2012 to 2015 were reviewed retrospectively to identify all cases of SSCC, SUM, and SSCC-SUM. For patients with SSCC-SUM, clinical characteristics were obtained from electronic medical records. All histologic specimens were reviewed by 3 dermatopathologists.

RESULTS

The medical records of 456 patients were reviewed. SSCC was diagnosed in 78 (17%), SUM was diagnosed in 63 (14%), and SSCC-SUM was diagnosed in 9. Patients with SSCC-SUM accounted for 11% of those with a diagnosis of SSCC (9 of 78) and 14% of those with a diagnosis of SUM (9 of 63).

LIMITATIONS

This was a single-institution retrospective study.

CONCLUSION

The association of SSCC and SUM is relatively frequent in patients with SUM and warrants further consideration to understand the underlying mechanisms involved.

[Dark nail: clinical findings, diagnostics and therapy of melanonychia]

BACKGROUND

A dark colored pigmentation of nails can be due to a subungual malignant melanoma. There are, however, many other benign causes and this differentiation is an important challenge in dermatological practice.

PROBLEM

When should nail pigmentation be clarified by histological investigations?

MATERIAL AND METHODS

This article gives a survey of the literature on this topic and a review of own experiences with clinical case examples. The various causes of melanonychia are presented and criteria for the early recognition of melanoma of the nail matrix are formulated.

RESULTS

The width and depth of color of longitudinal melanonychia do not allow any conclusions on the dignity. If the nail striation is proximally broader than distally, this is evidence of a proliferative event. Confirmation of a subungual hemorrhage does not exclude a malignancy per se. Also detection of pigmentation due to fungi does not exclude the additional presence of a subungual melanoma. A systematic clinical analysis using clear criteria leads to a working diagnosis and suitable treatment.

CONCLUSION

An early and correct designation of nail pigmentation can avoid unnecessary nail interventions but can also be life saving.