New Zealand patients have a higher melanoma burden in sentinel nodes and completion lymphadenectomy than patients in MSLT-II.

New Zealand has the highest rate of melanoma-related mortality in the world. Access to immunotherapy and radiology is limited and surgical treatment of regional disease remains important. A recent pilot study of a single health district observed a higher nodal melanoma burden than was reported in the second Multicentre Selective Lymphadenectomy Trial (MSLT-II). In this study, a series of regional censuses were undertaken covering the 10 years immediately prior to the publication of MSLT-II. The study population was seven District Health Boards covering 62.2% of the population of New Zealand across a 10-year period preceding MSLT-II. The primary outcomes measured were the size of sentinel lymph node metastases and non-sentinel node (NSN) positivity on completion lymph node dissection (CLND) for patients with a positive sentinel lymph node biopsy (SLNB). In the 2323 SLNB identified, the mean sentinel lymph node metastatic deposit size was larger compared to MSLT-II (2.55 vs. 1.07/1.11 mm). A greater proportion of New Zealand patients (44.2%) had metastatic deposits larger than 1 mm compared to MSLT-II (33.2/34.5%) and the rate of non-sentinel node involvement on CLND was also higher (22.2% vs. 11.5%). These findings indicate that New Zealand is a high-risk population for nodal melanoma metastases. Due to these differences, the conclusions of MSLT-II may not be able to be applied to melanoma patients in the 7 regions studied in New Zealand.

Porokeratosis: a differential diagnosis to consider in benign lichenoid keratosis.

Porokeratosis is a disorder of keratinization with many clinical variants. The histological hallmark feature of porokeratosis is a cornoid lamella. Other accompanying features include lichenoid inflammation, atrophy towards the centre of the lesion, dermal cytoid bodies, and adjacent lichenoid changes. Lichenoid keratosis is a benign cutaneous condition, thought to largely represent a degenerating seborrheic keratosis or solar lentigo. The classical histologic appearances are characterized by parakeratosis, epidermal acanthosis, and a dense band of lichenoid lymphocytic infiltrate. Since a lichenoid inflammatory reaction pattern can be seen in porokeratosis it has the potential to be misdiagnosed as a lichenoid keratosis if the cornoid lamella is not identified or missed due to sampling selection. We critically review 104 cases of benign lichenoid keratosis to establish whether any of these cases had features to support a diagnosis of porokeratosis. With 9.6% of cases considered for re-classification, we review clues to reaching this histologic diagnosis.

Melanoma sentinel lymph node biopsy and completion lymph node dissection: A regional hospital experience.

Completion lymph node dissection (CLND) following positive sentinel lymph node biopsy (SLNB) for cutaneous melanoma is a topic of controversy. The second Multicenter Selective Lymphadenectomy Trial (MSLT-II) suggested no survival benefit with CLND over observation amongst patients with a positive SLNB. The findings of the MSLT-II may have limited applicability to our high-risk population where nodal ultrasound and non-surgical melanoma treatment is rationed. In this regional, retrospective study, we reviewed primary melanoma, SLNB and CLND histopathological reports in the Bay of Plenty District Health Board (BOPDHB) across a 10-year period. The primary outcomes measured were size of sentinel lymph node metastases and non-sentinel node (NSN) positivity on CLND for patients with a positive SLNB. In the 157 SLNB identified, the mean sentinel lymph node metastatic deposit size was larger in BOPDHB compared with MSLT-II (3.53 vs 1.07/1.11mm). A greater proportion of BOPDHB patients (54.8%) had metastatic deposits larger than 1mm compared with MSLT-II (33.2/34.5%) and the rate of NSN involvement on CLND was also higher (23.8% vs 11.5%). These findings indicate that the BOPDHB is a high-risk population for nodal melanoma metastases. Forgoing CLND in the context of a positive SLNB may place these patients at risk.

Number of levels required to assess Breslow thickness in cutaneous invasive melanoma: An observational study.

BACKGROUND: Melanoma is a globally significant and highly prevalent disease, with Breslow thickness widely recognized as the most important histologic indicator of prognosis. In the newest edition of the AJCC Cancer Staging Manual, changes have been made to the definition of stages based on Breslow thickness. It is therefore imperative we accurately measure the Breslow thickness in a standardized fashion. METHODS: Our study aimed to identify the optimal number of levels required to measure Breslow thickness. We reviewed archived cases of previously diagnosed invasive melanomas and assessed whether there was a change of T stage with the greater number of levels examined. RESULTS: In our series of 54 cases, 10 (18.5%) cases were upgraded as additional levels were examined, statistically significant at the threshold of three levels. CONCLUSIONS: Our data suggests the optimal number of levels to examine is 3, with no benefit seen in further levels up to 10.

Presence of stratum corneum serum in non-palmoplantar psoriasis.

BACKGROUND: Psoriasis is a common, chronic skin eruption characterized by abnormal hyperproliferation of the epidermis. When assessing psoriasis histologically, it is historically considered a "dry" disease, with significant amounts of serum not expected within lesional stratum corneum. However, this specific feature is not often mentioned within the literature. A retrospective study was undertaken to assess prevalence of serum within stratum corneum in cases of non-palmoplantar psoriasis. METHODS: We evaluated 27 specimens diagnosed histologically as psoriasis between January 2015 and June 2016. In addition to serum, we assessed for psoriasiform hyperplasia, hypogranulosis, suprapapillary thinning and parakeratosis with neutrophils. The cases were then categorized as either diagnostic for, or consistent with, psoriasis and were followed up with clinicians to assess whether the clinical course was consistent with psoriasis. RESULTS: A total of 27 hematoxylin and eosin (H&E)-stained biopsies were examined from 21 patients, with periodic acid-Schiff (PAS) performed on 20 of the biopsies. Of these, 12 biopsies had serum present (44.4%). Of the 12 lesions considered to clinically and histologically represent psoriasis, 5 (41.7%) had serum. CONCLUSION: Our results suggest serum within stratum corneum is possibly an acceptable feature within the spectrum of psoriasis histopathology and should not necessarily detract from the diagnosis.

Follicular Porokeratosis, a Porokeratosis Variant.

Porokeratosis derives from a process of abnormal keratinization, resulting in clinical and histologic variants. Follicular involvement is infrequently described, with previous suggestions that it may represent a distinct condition. We describe a case of typical disseminated superficial actinic porokeratosis with additional clinically prominent folliculocentric keratosis. Histologically, this represented follicular cornoid lamellae. These findings support follicular porokeratosis as an anatomic site variant of porokeratosis, as opposed to a distinct condition. We also want to raise awareness of this variant which clinically should be considered when presented with a discrete papular keratotic eruption.

Squamous cell carcinoma with enteric adenocarcinomatous differentiation.

We report a highly unusual case of a primary cutaneous squamous cell carcinoma (SCC) with intermixed enteric-type adenocarcinomatous dedifferentiation and a small component of undifferentiated mesenchymal differentiation. We believe this is the first time this form of phenotypic plasticity has been described in cutaneous SCC.

Mitotic Activity in Juvenile Benign Nevi.

Melanocytic nevi are submitted for histological evaluation primarily to exclude a malignant process. Mitotic figures are one of the factors used in this assessment. However, there is a lack of data on mitotic activity in juvenile benign nevi. The authors assessed 114 cases of benign melanocytic nevi in children aged 0-15 (inclusive) years old by counting the mitoses present in 2 sections of hematoxylin and eosin-stained tissue. The authors then calculated the proportion of cases in which mitotic activity was present, and the average number of mitoses per case for each age group to get the mitotic rate. The authors found that there was at least 1 mitoses present in 40.4% of cases, and that the mitotic rate decreases in older children compared with younger children. This highlights the need for careful consideration of the significance of a mitotic figure in juvenile pigmented lesions, to ensure the lesion is not overinterpreted as malignant.

Pigmented Porokeratosis. A Further Variant?

Porokeratosis is a clonal disorder of keratinization characterized by the presence of the cornoid lamella. A number of variants of porokeratosis have been described, based on the clinical features and histologic features of the lesions. The authors present a case of porokeratosis with prominent melanocytic hyperplasia, which was biopsied to clinically exclude melanoma. The authors retrospectively studied cases of porokeratosis to look for the presence of melanocytic hyperplasia. Melanocytic hyperplasia was identified in 8 of 31 cases (25.8%). All of the cases except the index case were clinically nonpigmented but arose in solar damaged skin. This case represents a distinct variant of porokeratosis, and the authors propose the designation pigmented porokeratosis. Melanocytic hyperplasia is a benign condition, and it is important that this is not histologically confused with melanoma in situ, particularly in a context of clinically pigmented lesion. Increased recognition of pigmented porokeratosis is essential to avoid an erroneous diagnosis of melanoma in situ.

Assessment of tumor mitotic rate in primary cutaneous malignant melanomas 1 mm or less in thickness.

BACKGROUND: Tumor mitotic rate in thin melanomas is recognized as a powerful, independent prognostic factor predicting survival. In nonulcerated cases, the presence of any dermal mitotic activity upstages the disease to pT1b. The extent to which tissue should be histologically examined to assess mitogenicity, however, has not been studied. OBJECTIVE: We sought to determine whether in staging thin melanomas, there is a significant benefit in examining numerous tissue sections containing invasive disease. METHOD: In all, 71 cases of thin cutaneous melanomas diagnosed between January 2012 and June 2013 were identified after a search performed on the Pathlab database. The slides were retrieved and reviewed retrospectively, comparing the identification of the first dermal tumor mitotic figure, if present, at 4 check-points: the first, third, fifth, or tenth tissue section examined. RESULTS: A statistically significant difference in identification of the first dermal mitotic figure was found in examining 1 versus 3 tissue sections (P = .0411). No significant difference was found in examining numerous tissue sections. LIMITATIONS: This was a retrospective study from a single institution with a limited number of participants. CONCLUSION: In staging thin melanomas without ulceration, the optimal number of sections to assess is 3. No additional benefit is gained by examining numerous tissue sections.

MITF positivity in atypical fibroxanthoma: a diagnostic pitfall.

Microphthalmia transcription factor (MITF) is an established melanocytic marker originally credited with a high degree of specificity. We report a series of 11 atypical fibroxanthoma (AFX) from 2 laboratories showing positive MITF staining. Although there are multiple case reports illustrating MITF staining in a range of tumors, aberrant staining in AFX has not been previously reported. Awareness of the possibility of MITF positivity in AFX is important to avoid a misdiagnosis of melanoma. We also report positive MITF staining in 2 nonneural granular cell tumors and discuss the overlap with the granular subtype of AFX.

Porokeratosis ptychotropica: a rare and evolving variant of porokeratosis.

Porokeratosis ptychotropica represents a rare and under-recognized variant of porokeratosis. There are also alternative descriptions for this disorder in the literature. Since its original description in 1995, additional characteristic features have been showed in case reports published in the literature. These cumulative reports, although still limited in numbers, have helped to further shape and define this entity. A case report and review of published literature on this unusual entity are presented. The specific combination of clinical, morphological and histopathological characteristics that can facilitate recognition of the disorder is discussed. There has been a call for uniformity in terminology and a suggestion for alternative terminology has been made. However, we discuss why the earlier term, porokeratosis ptychotropica, is still preferred.

Differentiation between malignant melanoma and Spitz tumour has improved over the past decade due to modern pathological techniques.

A 10-year-old boy was diagnosed with a thick neurotropic melanoma of the lip in 2002. He is alive and well without evidence of disease recurrence 10 years later. We applied modern pathologic techniques to this lesion to highlight recent advances in melanoma diagnostics.

5% fluorouracil chemowraps in the management of widespread lower leg solar keratoses and squamous cell carcinoma.

Elderly patients with extensive hypertrophic solar keratoses and squamous cell carcinoma on the lower legs can pose significant management challenges. Typically these patients require surgical treatment which is complicated by comorbidities and poor background lower leg skin. 5% fluorouracil chemowraps provides a useful alternative technique for the management of diffuse hypertrophic solar keratoses and as an adjuvant, and in some situations as a palliative treatment, for squamous cell carcinomas on the lower legs.

Low clinically significant rate of recurrence in benign nevi.

The recurrence rate of benign nevi has been infrequently reported and primarily as a rate of clinical recurrence. The aim of this study was to document the rate of recurrence leading to re-excision of previously biopsied nevi (the clinically significant recurrence rate). Nevi undergoing primary biopsy with a minimum 5 years follow-up were reviewed in a pathology database for recurrence requiring a further excision. A total of 1035 nevi were reviewed including 196 dysplastic nevi. Twenty six percent of nevi had a positive margin, more common in shave and punch than ellipse biopsied lesions. Three cases recurred requiring re-excision resulting in a pathology recurrence rate of 0.3%. These 3 cases showed benign changes and 2 were originally excised with clear margins. The rate of recurrence requiring re-excision is very low at 0.3%. This suggests that few cases of clinical recurrence are re-excised. Re-excision of benign nevi including mild and moderately dysplastic nevi may not be necessary.

Where pigmented pilomatricoma and melanocytic matricoma collide.

Pilomatricoma and matricoma are 2 benign epithelial tumours derived from the hair matrix. Although containing the same constituent cells, the silhouette differs, with matricoma comprised of a predominantly solid basaloid proliferation with only focal areas of shadow cell formation. The recently described melanocytic matricoma appears to be a similar tumor with numerous interspersed melanocytes. We studied retrospectively 28 pilomatricomas and 2 pilomatrical carcinomas to check for the presence of melanocytes using immunohistochemical staining to S-100 and Melan-A. Three cases of pilomatricoma with prominent melanocytic hyperplasia were detected, confirming this as a rare (11%) occurrence. Both cases of pilomatrical carcinoma were negative. Comparison of these tumors with a further case of melanocytic matricoma led to a critical analysis of the relationship of pilomatricoma, matricoma, and melanocytic matricoma. Although further comparison is required, we suggest that melanocytic matricoma may be simply a pigmented melanocytic variant of matricoma, in the same way as we accept pigmented pilomatricoma as a variant of pilomatricoma. In this report we provide features that may be used to discriminate matricoma and pilomatricoma and their pigmented variants.