Melanoma arising from a plaque‐type blue naevus with subcutaneous cellular nodules of the scalp

Plaque‐type blue naevus (PTBN) is a very rare variant of blue naevus (BN). The potential malignancy of subcutaneous cellular nodules (SCN) in PTBN was discovered in 2012, and there is currently no clear consensus on prognostic factors or management guidelines of such lesions. PTBN on the scalp have not been described in the literature. We report the clinical, histopathological and immunohistological features of a 50‐year‐old man who presented with a 30‐year history of scalp PTBN, with malignant proliferation of nodular elements and fatal outcome 8 years later. This case suggests that long‐term monitoring of patients with PTBN is required. Early surgical removal of such lesions should be considered, especially in the presence of any case of enlargement or change.     

Melanoma ex blue nevus: two cases resembling large plaque‐type blue nevus with subcutaneous cellular nodules

Large plaque‐type blue nevi with subcutaneous cellular nodules are rare tumors occurring on the trunk with deep extension into underlying soft tissues. The histopathologic appearance consists of deep nodules resembling cellular blue nevi with interspersed foci of common blue nevus. Conservative management has been recommended, and metastases have not been observed. This report discusses two cases with microscopic features of large plaque‐type blue nevi with subcutaneous cellular nodules in which comparative genomic hybridization showed chromosomal aberrations typical of melanoma. In both cases, the nodules showed gains involving chromosome 6p and losses involving chromosome 6q, which are among the most commonly found aberrations in melanoma. These copy number changes were not present in the less cellular surrounding areas that appeared characteristic of blue nevus. These cases illustrate that large blue nevi with a deep, multi‐nodular configuration should be interpreted with caution, and that superficial biopsies of such lesions can be misleading. Molecular techniques can provide valuable insights in these types of difficult melanocytic neoplasms.     

The spectrum of benign dermal dendritic melanocytic proliferations

Dermal melanocytoses (DMs) comprise a heterogeneous group of benign lesions, located on skin and mucous membranes, characterized by dendritic melanocytes in the dermis. Although they share common histopathological features, some variants may present only as bluish or grey patches, some only as papules/nodules/plaques and others may show combination of all of these lesions. Despite the fact that blue naevus (BN) is typically characterized with papulonodular lesions, its variants may show all of the aforementioned presentations. Mongolian spot, naevus of Ota and naevus of Ito are patchy DMs distinguished by their specific localizations. Apart from these classical forms, many atypical variants without unique clinicopathological characteristics have been described in the literature making the nomenclature of DMs more complicated. However, congenital dermal melanocytosis and acquired dermal melanocytosis seem to be crucial umbrella terms that encompass all patchy DMs in atypical locations. Papules or subcutaneous nodules on patchy lesions and association of epidermal pigmentation presenting as brownish patches may be encountered as rare features of DMs. On the other hand, delayed‐onset subcutaneous nodules may be typical presentations of melanoma in patchy DMs; therefore, they deserve special attention. Large plaque‐type BN with subcutaneous cellular nodules is a newly described entity, harbouring clinical features of various DMs together and has a high risk of melanoma. The whole spectrum of dermal dendritic melanocytic proliferations is discussed including novelties and controversial issues.     

Recurrent nodules in a periauricular plaque‐type blue nevus with fatal outcome

Plaque‐type blue nevus is a rare variant of blue nevus characterized by grouped nodules displaying histomorphological features of a cellular blue nevus. We report the clinical, histopathologic and immunohistologic features of a patient with recurrent nodules in a periauricular plaque‐type blue nevus with malignant transformation and fatal outcome. The nevus was characterized clinically by childhood onset, with slow enlargement during adolescence. At age 16, the patient presented with nodules located retroauricularly. Several surgical excisions with the intent of complete removal of the nodules and the nevus were performed. Histopathological, dermal and subcutaneous proliferations of pigmented melanocytes with melanophages were detected. The nodules showed some cellular atypia and few mitotic figures, (Ki67 estimated <1%). At age 20, the patient developed new nodules retroauricular, with histopathology similar to previous lesions; however, the proliferation rate was higher. A comparative genomic hybridization (CGH) showed chromosomal changes indicative of melanoma. At age 25, the patient developed multiple liver metastases and died after 4 weeks. A sequencing of the tumor DNA revealed a GNAQ Q209P mutation, whereas mutations of GNA11, BRAF, NRAS and cKIT were not detected. This case shows that nodules in plaque‐type blue nevus may have malignant potential which may be uncovered by CGH.     

Subungual and periungual congenital blue naevus

Subungual pigmented lesions should raise concern about malignant melanoma. Blue naevus of the nail apparatus is a rare entity, with only ten cases described in the literature. We report a 21-year-old Hispanic woman with a slowly enlarging 1.7 × 2.3-cm subungual and periungual pigmented plaque present since birth on her right second toe. Initial biopsy was consistent with a blue naevus of the cellular type and, given the recent clinical change and periungual extension, complete excision was recommended. The entire nail unit was resected down to periosteum with prior avulsion of the nail plate. Reconstruction was performed with a full-thickness skin graft. Follow up at 1 year revealed well-healed graft and donor sites with complete return of function. We present a case of a congenital subungual and periungual blue naevus of the cellular type and review the literature on this rare presentation of a congenital blue naevus.     

Malignant blue naevus with distant subcutaneous metastasis

Malignant blue naevus is a distinct but rarely documented variant of malignant melanoma, and we describe the triple recurrence of a suprapatellar cellular blue naevus over 12 years in a middle-aged woman. Staging investigations revealed a distant subcutaneous metastasis of the right thigh. Immunohistochemistry of the primary lesion and all recurrences showed S-100, HMB-45, NK1/C-3 and Ki-67 positive cells. However, non-malignant cellular blue naevi from five consecutive other patients were all Ki-67 negative. The change from negative to positive Ki-67 responsivity may therefore be a valuable marker of malignant and metastatic potential in early cellular blue naevi.     

Nevo azul en placa

—Plaque-type blue nevus or agminated blue nevus is a melanocytic lesion composed of an aggregation of multiple blue plaques in a circumscribed area.Herein, we describe a case of a 22-year-old man with a plaque-type blue nevus on his right shoulder who developed subcutaneous cellular nodules.     

A cellular blue nevus with pigmented epithelioid melanocytoma‐like pattern on the ipsilateral upper arm associated with a congenital plaque‐type blue nevus on the hand

A 36‐year‐old man presented with a subcutaneous nodule on the right upper arm. A small nodule had developed 8 years earlier, and grew in size, accompanied by a tingling sensation and numbness. In addition, he had a bluish irregular patch on the right hand since birth, which crossed from the palm to the dorsal hand. Skin biopsies from the hand showed a heavily pigmented melanocyte proliferation in the dermis with perieccrine, perivascular, and perineural involvement, and a diagnosis of congenital plaque‐type blue nevus was made. The tumor on the arm was located closely along the median nerve, and was observed as a large black pedunculated round tumor. Histopathologically, the tumor on the arm consisted of densely packed tissue with nevoid cells without atypia in the larger nodular part, and heavily pigmented spindle and epithelioid melanocytes in the slender stalk area, which was diagnosed as cellular blue nevus with pigmented epithelioid melanocytoma‐like pattern. Next‐generation sequencing revealed GNAQ mutations in the hand lesion, and in the lesions on the arm. This case suggests that the areas of skin following the same neural distribution of a congenital plaque‐type blue nevus on the extremities should be followed up for secondary changes.     

Epithelioid blue naevus of the genital mucosa: report of four cases

Epithelioid blue naevi are an unusual cytological variant of blue naevus that have been recently described mostly in patients with the Carney complex, although they may also occur in isolation. This variant of blue naevus is composed of melanin-laden polygonal epithelioid melanocytes situated within the dermis. The neoplastic cells show no maturation with progressive depth of dermal infiltration and, in contrast with the usual stromal changes in blue naevi, epithelioid blue naevi exhibit no dermal fibrosis. We describe four cases of epithelioid blue naevus located on the genital mucosa in four patients with no evidence of the Carney complex. Three male patients showed an epithelioid blue naevus on the mucosa of the glans penis and a female patient had a lesion of the right labium minoris. Histopathologically, the lesions consisted of entirely intradermal melanocytic naevi composed mostly of heavily pigmented epithelioid melanocytes involving the dermis of the genital mucosa. Immunohistochemically, in all cases, epithelioid melanocytes expressed immunoreactivity for S-100 protein, HMB-45, Melan-A and MiTF antibodies.     

Epibulbar complex choristoma and hemimegalencephaly in linear sebaceous naevus syndrome

Epidermal naevus syndrome is a group of congenital syndromes comprising epidermal naevi associated with a variety of developmental abnormalities of the ocular, nervous, skeletal, cardiovascular and urogenital systems. We describe a case of an 8‐month‐old boy with a brown alopecic plaque on his face and scalp and a vascularized epibulbar mass involving the entire cornea, which had been present since birth. Histopathological examination identified sebaceous naevus in combination with complex choristoma. Magnetic resonance imaging of the brain showed hemimegalencephaly.     

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.     

Postirradiation pseudosclerodermatous panniculitis with involvement of breast parenchyma: a dramatic example of a rare entity and a pitfall in diagnosis

Postirradiation pseudosclerodermatous panniculitis is a rare complication of external beam radiotherapy. This inflammatory process typically presents as an erythematous indurated plaque in a previously irradiated region of skin. To date, 13 cases have been reported worldwide. We present a case of a 70‐year‐old female who received breast irradiation following conservation surgery for invasive breast carcinoma. In her third year of follow‐up, she developed an enlarging mass, involving the subcutis and underlying breast tissue, associated with mammographically detected coarse calcifications and density, at the surgical site. This was deemed highly suspicious of recurrent malignancy. Following several benign needle core biopsies, she had an excision of the mass. This revealed a lobular panniculitis and irradiation‐induced vascular changes affecting subcutaneous fat and underlying breast tissue. This is the 14th reported case of this rare entity. It is unique in the degree of involvement, affecting breast parenchyma as well as subcutaneous fat, and in its corresponding dramatic clinical and radiographic manifestations.     

Cellular blue naevus

A 31-year-old man had asymptomatic, stationary, 1.5X2 cm, shiny, smooth, dark blue nodule on dorsum of right hand since 12-14 years. In addition he had developed extensive eruption of yellow to orange papulonodular lesions on extensors of limbs and buttocks since one and half months. Investigations confirmed that yellow papules were xanthomatosis and he had associated diabetes mellitus and hyperlipidaemia. Biopsy of blue nodule confirmed the clinical diagnosis of cellular blue naevus. Cellular blue naevus is rare and its association with xanthomatosis and diabetes mellitus were interesting features of above patients which is being reported for its rarity.     

A Mimic of Self‐Healing Juvenile Cutaneous Mucinosis?

A 14‐year‐old boy presented with a chronic history of atypical papular mucinosis consisting of multiple subcutaneous nodules and confluent papular skin lesions. He initially presented at age 2 years with the rapid onset of numerous subcutaneous nodular lesions that completely resolved over a period of years. Clinical and histologic evidence, together with his clinical course, were suggestive of self‐healing juvenile cutaneous mucinosis (SHJCM), but a few years later, during childhood, he experienced a recurrence of the subcutaneous nodules involving the limbs, trunk, and face, in addition to new findings of multiple flesh‐colored papules coalescing into plaques on his neck and back. Although his early childhood course and histologic picture were suggestive of SHJCM, the progressive nature of his disorder is not like that seen in SHJCM and appears different from other reported disorders involving cutaneous mucinosis.     

Nodular lesions arising in a large congenital melanocytic naevus in a newborn with eruptive disseminated Spitz naevi

Congenital malignant melanoma within a pre‐existing large congenital melanocytic naevus (CMN) is exceedingly rare. Its incidence is difficult to determine due to the small number of reported cases and because of problems associated with diagnosis. Some benign nodular proliferations (called proliferative nodules) arising in CMN, while rare, are significantly more common and can mimic malignant melanoma clinically or histologically. There are no reported cases of congenital melanoma or benign proliferative nodules in CMN in patients who also had eruptive disseminated Spitz naevi. We describe a girl who was noted to have a dark‐brown plaque with several large erythematous nodules affecting the scalp at delivery, in addition to multiple erythematous dome‐shaped papules that developed in a disseminated manner over several months, beginning at 10 days of age. It was difficult, not only clinically but also histologically, to determine the benign or malignant nature of all of these lesions. As primary cutaneous melanoma, atypical proliferative nodules in CMN, bland CMN or CMN with foci of increased cellularity and Spitz naevi show clear differences in the genetic aberration patterns, comparative genomic hybridization (CGH) could be a diagnostic help in ambiguous cases such as this. CGH performed on this patient showed multiple DNA copy number changes in the most atypical nodule, but such alterations could not be found in the remainder of the lesions. CGH showed differences between the nodular lesions that occurred in the CMN and helped us in supporting the diagnosis of this unique case of benign proliferative nodules and a possible congenital melanoma arising in a large CMN, associated with multiple widespread eruptive Spitz naevi.     

Familial multiple blue naevi

Blue naevi are benign melanocytic neoplasms. They are usually solitary blue or blue-black nodules or plaques. Multiple blue naevi have been reported rarely and there is one report of familial solitary blue naevus. However, familial multiple blue naevi have not been reported previously. We report the case of a family with multiple blue naevi occurring in three generations with an autosomal-dominant inheritance pattern.     

Myopericytoma proliferating in an unusual anastomosing multinodular fashion

We herein describe a case of myopericytoma that proliferated in an unusual fashion. Myopericytoma is described as a group of rare, benign, dermal or subcutaneous tumors that are characterized histologically by a striking, concentric, perivascular proliferation of spindle cells and showing apparent differentiation towards perivascular myoid cells. Myopericytoma forms a morphological continuum with myofibroma/myofibromatosis, glomus tumor and angioleiomyoma. The patient was a 64‐year‐old woman who demonstrated a recurrent ulcer on an atrophic plaque on her left shin. A histopathological examination of the plaque demonstrated that tumor cells proliferated in an anastomosing multinodular fashion along the vessels in the dermis and subcutaneous tissue. In those nodules, there were numerous, small, concentric proliferations of myoid‐appearing spindle cells around small vascular lumina. The present case is an unusual example of myopericytoma, manifesting in a characteristic anastomosing, multinodular, infiltrating fashion.     

A case of subcutaneous sarcoidosis in a patient with Cushing's syndrome

A 41-year-old female visited our department complaining of asymptomatic subcutaneous nodules on the right forearm. She had been diagnosed as having Cushing syndrome due to an adrenal tumor 5-months previously. After she underwent surgery for the adrenal tumor, the subcutaneous nodules gradually increased in number. Physical examination showed ill-defined plate-like subcutaneous indurations on the bilateral lower extremities, buttocks, and right forearm. A biopsy of one of the subcutaneous indurations showed non-caseating epithelioid cell granulomas involving the hypodermis and subcutaneous tissues. The patient was diagnosed as having sarcoidosis based on the Japan Society of Sarcoidosis and Other Granulomatous Disorders 2015 criteria. Skin lesions decreased in size and had completely disappeared. Although the mechanism is unknown, there may be a possibility that the activity of sarcoidosis is suppressed by high cortisol concentrations due to Cushing syndrome.     

HMB 45 positive balloon cells in combined nevi]

The combined naevus is made up of two components, one resembling a melanocytic naevus, the other a blue naevus. Clinically, these naevi do not give any obvious cause for concern. Histological examination shows that the combined naevus consists of a superficial melanocytic naevus and a deep-seated spindle cell blue naevus. There is a rare variant in which the pigmented spindle cells of the "blue" naevus are replaced by large balloon cells varying in melanin content. These combined naevi, because of the large cells with abundant cytoplasm, closely resemble malignant melanoma. As a further aid to diagnosis we used the monoclonal antibody HMB 45. In our study, the vesicular cells in all seven combined naevi examined reacted strongly with HMB 45. It is suggested that HMB 45 is not always helpful in differentiating between melanoma and naevi.     

Composite cutaneous lymphoma of diffuse large B‐cell lymphoma‐leg type and subcutaneous panniculitis‐like T‐cell lymphoma

Composite lymphoma (CL) is a rare disease defined by the occurrence of two distinct lymphomas within a single tissue at the same time. We present the case of an 89‐year‐old male with a clinical history of immunoglobulin M monoclonal gammopathy of undetermined significance. The patient presented cutaneous eruption of nodules on the right bottom and arm. An excisional biopsy revealed cutaneous infiltration composed of two components. The first one consisted of large B‐cells with CD20+/MUM1+/BCL2+ phenotype whereas the second one involved the subcutaneous fat in a panniculitic manner, and was CD3+/CD8+/granzyme B+/TCRβF1+. The final diagnosis was CL of primary cutaneous large B‐cell lymphoma‐leg type (PCLBCL‐leg type) and subcutaneous panniculitis‐like T‐cell lymphoma (SPTCL). We report and characterize for the first time coexistent PCLBCL‐leg type and SPTCL in a patient.