Value of high resolution ultrasound in determination of vertical tumor thickness in malignant melanoma of the skin

The maximal thickness of a primary malignant melanoma of the skin can be determined preoperatively by means of modern high-frequency ultrasound scanners (20 MHz). In this way operative therapy can be planned and the minimal excision margins can be determined before surgery. The present study demonstrates a strong correlation (r = 0.97) between preoperative ultrasound and postoperative histometric determination of tumour thickness in 72 primary malignant melanomas. The study showed, however, that ultrasound scanners cannot distinguish unequivocally between histologically confirmed tumour cell aggregates and subtumoral remnants of a benign melanocytic naevus or subtumoral lymphocytic infiltrates. In these cases, determination of tumour thickness by ultrasound yields higher values for thickness than do histological examinations. In addition, tumour cell aggregates that are smaller than the lower limit of scanner resolution, are very close to the main tumour mass, or have infiltrated the deeper dermis cannot be measured accurately. In these cases, ultrasound examination underestimates the tumour thickness.     

(17) Histopathology of giant congenital melanocytic naevi: implications for treatment

Giant hairy naevi pose not only cosmetic problems, but also therapeutic difficulties because of the increased risk of malignant melanoma. Prophylactic full thickness excision and grafting have previously been recommended for such lesions, but because of the large size this is not always practical. Following observations that in the neonatal period, naevus cells are superficial (predominantly in the papillary dermis) and only later migrate into reticular dermis, some authors have suggested that dermabrasion or shaving of the naevi must be performed soon after birth, as an alternative therapy. We studied 26 children with giant congenital melanocytic naevi to assess: (i) the histological progression with age; (ii) correlation of clinical and histological appearance; and (iii) results of shaving in the treatment of these naevi.
Initial biopsies revealed that naevus cells often occupy the entire dermis, even in the neonatal period, and not infrequently involve the subcutis. Melanocytes showed little organization into nests.
Follow-up biopsies of all naevi showed no change in histological pattern or progression in depth with age, despite changes in clinical appearance.
Post-shaving biopsies revealed that although the epidermis and sometimes the papillary dermis were removed, all the deeper dermal, subcutaneous and fascial components of the naevi remained.
In conclusion our data suggest that: (i) many congenital melanocytic naevi already show deep dermal involvement in the neonatal period; this does not support the hypothesis that naevus cells migrate into the dermis during infancy; (ii) there is no change in naevus depth with age; (iii) shaving does not remove all the naevus cells, and should only be considered as a cosmetic procedure, Three cases showed regeneration of melanocytes following shaving, similar to what is described as the 'pseudomelanoma' phenomenon.     

Treatment options for giant congenital naevi

Giant congenital naevi (GCN) are disfiguring, potentially malignant pigmented naevi present at birth. The naevus cells in GCN are found throughout the dermis and sometimes penetrate the subcutaneous septa. It is claimed that superficial, more heavily pigmented and biologically different naevus cells reside in the upper dermis. Partial removal of these superficial naevus cells by dermabrasion, laser therapy, curettage or shave excision is less traumatic than excision surgery and produces an acceptable cosmetic result. However, none of these techniques or excision of GCN to superficial fat completely removes the risk of malignant transformation.     

A curious serendipitous finding: Spitz naevus combined with a syringoma

Combined tumours are often a serendipitous finding. Among the spectrum of melanocytic tumours, the co‐existence of different cell populations of the same linage is a well‐recognised phenomenon. Less commonly documented, but still well documented is the event of a melanocytic tumour in collision with an epithelial benign or malignant neoplasm. Exceptionally infrequent is however the collision of a Spitz naevus with an epithelial tumour. Here we report the clinical‐dermoscopic and histopathological findings of a Spitz naevus occurring in collision with a syringoma.     

Neonatal treatment of giant naevi.

A technique of curettage of giant congenital naevi in newborns was proposed by Moss in 1987. We used this technique in 6 children during the last 2 years. The long-term aesthetic results appear to be better than those observed after other methods of treatment. Light microscopy of the pigmented skin confirmed the presence of the majority of naevus cells in the upper dermis. For 3 patients, cultures of the curetted cells showed a melanocyte behaviour similar to that seen in malignant melanoma. These observations are limited to in vitro cultures and are not representative of the in vivo evolution as biopsies of the remaining naevus cells at 3 months of age did not show any malignant characteristics.     

Late‐onset bulky naevocytoma of the perineum masquerading as a malignant melanoma

Bulky naevocytoma of the perineum is a very rare variant of giant congenital melanocytic naevus (GCMN). It presents as a bulky naevocytic tumour in the perineal region with characteristic histological findings, such as extensive areas with a neural appearance called ‘lames foliacees’, formation of a pseudofollicular structure and extension of naevus cells between collagen bundles in a row called ‘Indian‐file’ pattern. We report a case of late‐onset bulky naevocytoma of the perineum in a 13‐year‐old girl. The patient presented with two bulky, pedunculated, heavily pigmented masses in the vulvar area that developed in a pre‐existing GCMN lesion, which began around puberty and caused severe gait disturbance. Given the possibility of malignant transformation, we conducted staged reduction surgery of the tumour masses, which were found to be intradermal naevi without evidence of malignancy. The patient's gait disturbance improved markedly after surgery.     

Okkultes dermales Primärmelanom in kongenitalem Nävuszellnävus

Malignant melanomas normally arise at the dermoepidermal junction. Development of these tumours in deeper layers of the dermis without having contact with the junction is rare. A small congenital melanocytic nevus localized in the region of the waist band was excised because of mechanical irritation; it had not shown any changes over years. A thorough examination of the whole body did not give any clue to a malignant melanoma. Histologically a compound nevus with the typical architecture of a congenital melanocytic nevus was found. In the deeper dermis there was an isolated nodule of extremely atypical melanocytes with minimal pigmentation of melanin. S100 antigen could be demonstrated throughout the whole tumour whereas HMB45 was only found at the dermoepidermal junction. There was no marking of the tumour cells with a pancytokeratin antibody. A histological relationship between the new tumour and a mixed tumour of the left testicle, which had been excised 3 years ago, could be excluded. We did not find any metastases neither by image-aided methods nor by sentinel lymph node biopsy.     

色痣和蓝痣的电镜观察

对4例色痣和2例蓝痣进行了电子显微镜观察.发现色痣的痣细胞中充满着许多第皿期和第N期黑素小体.蓝痣的黑素细胞在真皮深部.胞质中的黑素颗粒也相当多.在色痣和蓝痣的痣细胞中可见含黑素的大球形体.可能代表退行现象,也许是溶酶体吞噬了退变的黑素颗粒而形成的.最后讨论了色痣和蓝痣临床色泽差别的原因,蓝痣除黑素细胞部位深、受折光物理因素影响外.细胞中黑幸小体的含量、着色程度也有一定影响.     

Successful differentiation of Spitz naevus from malignant melanoma by microfluorometric analysis of cellular DNA content

Two cases of presumed Spitz naevus, whose diagnosis on clinical and histological grounds was uncertain, were examined for cellular DNA content using the technique of DAPI-DNA microfluoromety. They were compared with 20 cases, respectively, of clinically and histologically confirmed, Spitz, naevus, malignant melanoma and acquired pigmented naevus. The two Spitz naevi showed a diploid pattern in a distribution histogram of cellular DNA content. The pattern was similar to that of confirmed Spitz naevi and of acquired pigmented naevi but different from the aneuploid pattern of malignant melanomas. DNA index values of the two cases were within the range of confirmed Spitz naevi and different from those of malignant melanomas. The DAPI-DNA microfluorometric method thus provided confirmatory evidence for the diagnosis of Spitz naevus. The method appears to reflect sensitively the biological behaviour of tumour cells, and is a useful aid to the diagnosis of uncertain Spitz naevi.     

Extensive proliferative nodules in a case of giant congenital naevus

The rare presence of proliferative nodules in cases of giant congenital naevus can, in some cases, be potentially misdiagnosed as neonatal melanoma. We report here a case of multiple, proliferative nodules found in a giant congenital naevus lesion in a female neonatal patient diagnosed with neurocutaneous melanosis. Our initial clinical observations of this case suggested the possibility of primary cutaneous neonatal melanoma or skin metastasis from a melanoma in the meninges or elsewhere in the central nervous system. However, histological examination revealed no sign of melanoma, abnormal mitosis, necrosis or any malignant change. Pagetoid arrays of naevus cells in the junctional zone and myxoid changes present in a significant portion of the dermis led to the diagnosis of proliferative nodules. Distinct histological patterns seen in the proliferative nodules in our neonatal patient were useful to differentiate between benign pigmented nodular lesions in a giant congenital naevus and malignant melanoma, and reduced the chance of misdiagnosis.     

Neurothekeoma. A light and electron microscopy, histochemical and immunohistochemical study]

We report a 37-year-old man with neurothekeoma that developed on the tip of the nose. Histopathological examination revealed a lobulated myxoid dermal tumour. The tumour cells were spindle-shaped or bizarre configuration. In the lower part of the dermis the lesion contained abundant cells simulating glomus tumour or melanocytic naevus. Staining with S-100 protein, epithelial membrane antigen (EMA), neuron-specific enolase (NSE) and desmin were negative. The matrix of the tumour was positive for Alcian blue and periodic acid-Schiff (PAS). Electron microscopic examination showed that the lesion was composed of dendritic cells separated by abundant glassy matrix and varying amounts of collagen fibres. Some of the cells looked like fibroblasts, and others like perineurial cells. The histogenesis of the tumour is discussed with particular attention to histochemical, immunohistochemical, light and electron microscopic findings.     

Factor XIIIa in nodular malignant melanoma and Spitz naevi

The distribution of factor XIIIa-positive dermal dendritic cells was studied in a series of nodular malignant melanomas and compared with that seen in Spitz naevi. Two patterns of distribution were recognizable: (a) diffusely spread through the tumour and (b) located mainly at the periphery of the tumour. These did not correlate with the diagnosis of melanoma or Spitz naevus and the distribution appeared to be a function of growth pattern of the tumour. The diffuse pattern was the most common regardless of diagnosis and the distribution of factor XIIIa-positive cells is the same in malignant melanoma and Spitz naevi.     

Blue naevus with satellitosis mimicking malignant melanoma

Blue naevus is an acquired benign melanocytic naevus. It is a firm, sharply defined dark blue to grey-black papule or nodule, which is likely to arise from the arrested dermal melanocytes in the dermis. In the last few years, blue naevus has attracted much attention due to the recognition of new entities and to its confusion with malignant melanoma. We report a 69-year-old man who developed a blue-black nodular lesion with satellitosis on his scalp. Although clinically it was thought to be a malignant melanoma, histopathological investigation and conservative methods such as dermatoscopy and power Doppler ultrasonography did not confirm this diagnosis. Histopathological examination excluded malignant melanoma, as there were no cellular atypia and mitotic activity in either the nodular lesion or the satellitosis. Doppler ultrasonography confirmed the benign nature of the lesion. Dermatoscopic examination showed homogeneous steel-blue pigmentation with individual blue globules, dots and some brown veils, and confirmed the histopathological diagnosis. To the best of our knowledge, our case is the third reported case of a blue naevus with satellitosis mimicking malignant melanoma.     

BAP1‐inactivated melanocytic tumour with borderline histopathological features (BAP1‐inactivated melanocytoma): A case report and a reappraisal

We describe a case of BRCA1‐associated protein (BAP1)‐inactivated melanocytic tumour (BIMT) in a 22‐year‐old woman, documenting for the first time with dermoscopy its sudden development with the onset of an atypical vascular pattern within a Miescher naevus. The tumour was histopathologically atypical because of the presence of confluent pleomorphism, solid sheets of cells and grouped mitotic figures: these features were consistent with a melanocytic neoplasm with intermediate morphology (‘BAP1‐inactivated melanocytoma’; BIM) between a BAP1‐inactivated melanocytic naevus and a BAP1‐inactivated melanoma. The atypical histopathological features of the present case were different from the criteria quoted for BIM in the World Health Organization 2018 classification of skin tumours.     

Halo congenital naevus in a middle-aged patient with vitiligo

A case of halo congenital naevus is reported on the chest of a 56-year-old Asian woman with pre-existing vitiligo. The naevus measured 3.5 cm x 2 cm and underwent depigmentation around its periphery. Dermoscopic examination showed coarse pigment in the darker centre of the naevus and depigmentation in the surrounding halo. Light microscopy showed well-formed naevus cell nests with coarse melanin granules in the papillary dermis, and surrounding fibrosis. Melanocytes extended into reticular dermis, consistent with a congenital growth pattern. There was no evidence of malignancy. The epidermis was of normal appearance. S100 staining highlighted melanocytes in the dermis. Basal melanocytes were retained at the periphery of the naevus. Based on the clinical history and histological findings, a diagnosis of halo congenital naevus was made. The naevus was not excised.     

Spitz naevus of the toe

A 68-year-old Japanese woman presented with a brownish macule, containing two papules, on her left fourth toe. Histological examination revealed an intradermal epithelioid cell tumour with irregularly shaped, bizarre giant cells. In the upper portion of the tumour, the epithelioid cells contained abundant melanin. A low amount of 5-S-cysteinyldopa and a diploid DNA distribution histographic pattern were helpful in differentiating the lesion from malignant melanoma. This location of a Spitz naevus is exceptional.     

Melanocyte mutation in halo naevus and malignant melanoma?

Halo naevus cells on frozen sections react with sera from patients with benign halo naevus or with malignant melanoma. Halo naevus cells also react with our specifically absorbed heterologous antihuman malignant melanoma antiserum (RAMMA). Since the cytoplasm of all the naevus cells within the halo naevus react with sera from patients with malignant melanoma, this implies that the entire population of melanocytic cells in the mole has undergone mutation, because non-pathological skin melanocytes do not react.     

Can HLA-DR expression help in the routine diagnosis of malignant melanomas?

Two monoclonal antibodies, TAL-IB5 and LN3, directed at epitopes of HLA-DR were applied to a variety of benign naevi and malignant melanomas. Of the 31 naevi examined, 28 were completely unreactive. Weak staining was confined to a few cells in two intradermal naevi and there was more widespread reactivity in a halo naevus. Seven of the 25 primary cutaneous malignant melanomas were reactive with one or both of the antibodies and this reactivity was more marked in the deeper lesions. These positive cases were not felt to present diagnostic difficulties and it was concluded that TAL-IB5 and LN3 were not of use in distinguishing between benign and malignant melanocytic proliferations.     

Common blue naevus with satellite lesions: possible perivascular dissemination resulting in a clinical resemblance to malignant melanoma

We report a case of common blue naevus with polymorphous guttate and linear satellite lesions, thereby mimicking peripherally spreading malignant melanoma. Histopathologic examination showed that the naevus cells are clustered around blood vessels in the primary as well as satellite lesions, suggestive of spreading of the naevus cells along the perivascular space. Such biological behaviour resulting in a clinical manifestation of a malignant melanoma-like lesion is a rarity in common blue naevus, a benign cutaneous disorder that is devoid of a malignant potential, and has not been described before.     

Blue rubber bleb naevus syndrome associated with cortical blindness

An 83-year-old woman was admitted for investigation of sudden loss of vision. Extensive plum-purple papules and nodules involved her skin and lips but not mucosae. A cutaneous biopsy demonstrated irregular vascular cavernous channels in the dermis and subcutis; deeper vessels displayed smooth muscle. Blue rubber bleb naevus syndrome was diagnosed. This patient had no gastrointestinal symptoms, no family history of blue rubber bleb naevus syndrome, and only developed cutaneous signs after 60 years of age. Magnetic resonance imaging of the brain found multiple cerebral and cerebellar cavernomas with two larger foci of haemorrhage in both occipital lobes, with the largest in the right occipital lobe being associated with calcification. These most likely represent bleeding in relation to cavernomas believed to be the cause of decreased vision, predominantly in the left eye.