Histopathology of skin melanocytic lesions.

Melanocytic lesions are instable tumors, the genome of which and its changes determinate their morphology and biological properties. Intermediate lesions share histomorphological features of both, nevi and melanoma. Melanocytomas represent a group of them separated on the basis of recent molecular-biological studies. The article summarizes benign, intermediate, malignant and combined melanocytic skin lesions and offers practical recommendations for diagnosis.

A case of cutaneous collagenous vasculopathy associated with multiple myeloma and with a pathogenic variant of the glucocerebrosidase gene.

Cutaneous collagenous vasculopathy (CCV) is an extremely rare acquired microangiopathy of unknown etiology. The authors describe a case of a 68-year-old man, a carrier of a heterozygous pathogenic variant of the glucocerebrosidase (GBA) gene, who was diagnosed with CCV, revealing uncommon fibrinogen positivity in direct immunofluorescence. The patient was subsequently diagnosed with multiple myeloma. Treatment of the myeloma with combined chemotherapy including bortezomib, followed by autologous stem cell transplantation, led to significant reduction of cutaneous lesions. To the best of the authors' knowledge, this is the first published case of CCV in a carrier of a pathogenic variant of the GBA gene, associated with multiple myeloma and with significant regression of CCV after myeloma treatment. Direct immunofluorescence examination revealed an unusual fibrinogen deposition. Hypothetical causative role of bortezomib treatment was proposed regarding significant regression of CCV.

Human polyomavirus 6 and 7 are associated with pruritic and dyskeratotic dermatoses.

BACKGROUND: Human polyomavirus (HPyV)6 and HPyV7 are shed chronically from human skin. HPyV7, but not HPyV6, has been linked to a pruritic skin eruption of immunosuppression. OBJECTIVE: We determined whether biopsy specimens showing a characteristic pattern of dyskeratosis and parakeratosis might be associated with polyomavirus infection. METHODS: We screened biopsy specimens showing "peacock plumage" histology by polymerase chain reaction for HPyVs. Cases positive for HPyV6 or HPyV7 were then analyzed by immunohistochemistry, electron microscopy, immunofluorescence, quantitative polymerase chain reaction, and complete sequencing, including unbiased, next-generation sequencing. RESULTS: We identified 3 additional cases of HPyV6 or HPyV7 skin infections. Expression of T antigen and viral capsid was abundant in lesional skin. Dual immunofluorescence staining experiments confirmed that HPyV7 primarily infects keratinocytes. High viral loads in lesional skin compared with normal-appearing skin and the identification of intact virions by both electron microscopy and next-generation sequencing support a role for active viral infections in these skin diseases. LIMITATION: This was a small case series of archived materials. CONCLUSION: We have found that HPyV6 and HPyV7 are associated with rare, pruritic skin eruptions with a distinctive histologic pattern and describe this entity as "HPyV6- and HPyV7-associated pruritic and dyskeratotic dermatoses."

Two case reports of columnar dyskeratosis, an unusual keratinisation disorder.

Keratinisation disorders with distinctive histopathological patterns are few in number. We describe two men with unusual dermatosis, characterised by a distinctive pattern of focal dyskeratosis. Both men suffered from generalised dermatosis formed by verrucous red-brown plaques. Repeated skin biopsies showed the same histopathological pattern with foci of vertically oriented dyskeratotic cells. The dyskeratotic cells on the level of the stratum spinosum and granulosum were positive for AE1/AE3, CK-HW, CK-LS and CK116 immunostaining. PCR for HPV was negative. The similar clinical appearance of skin lesions in both patients together with their identical histopathological pictures seems to represent a unique clinicopathological condition that we believe is best described by the term 'columnar dyskeratosis'.

Dermatoscopy of pigmented actinic keratosis--a striking similarity to lentigo maligna.

BACKGROUND: Pigmented actinic keratosis (PAK) resembles lentigo maligna (LM) clinically and histopathologically in some cases. OBJECTIVES: To describe the dermatoscopical characteristics of this uncommon variant of actinic keratosis and evaluate whether these characteristics show common features with LM. OBSERVATIONS: We had the opportunity to examine a 78-year-old woman who presented with a PAK lesion on her face dermatoscopically and histopathologically. The pigmented pseudo-network had black and gray dust in some areas, which were the main dermatoscopical features. The pigmented pseudo-network was formed by an unhomogenous brown background interrupted by regularly distributed hair follicules. The hyperpigmentation was based not only on an increased presence of melanin within the keratinocytes in the basal and spinous layers of epidermis, but also an intensive apoptosis of keratinocytes connected to numerous melanophages. CONCLUSIONS: The dermatoscopical picture of PAK in this patient was practically indistinguishable from the early stage of LM. The authors considered that the pigmented atypical melanocytes' role in LM presenting as black dots in the dermatoscopical picture was displayed by the individually pigmented keratinocytes in PAK. The groups of melanophages presenting as gray dust were present in PAK similarly to their presentation in LM. The character of the pigmented pseudo-network is the same in the both afflictions. There is a need to examine other cases of PAK in order to decide whether our case represents a general pattern of the dermatoscopical picture.

Crystal storing histiocytosis of the skin associated with multiple myeloma.

BACKGROUND: Crystal storing histiocytosis (CSH) imitating rhabdomyoma is a very rare disease entity involving different tissues. The skin is involved in extremely rare cases. OBJECTIVES: To describe the clinical and histopathological characteristics in a patient with unusually extensive skin involvement. OBSERVATIONS: A 62-year-old woman presented with a large red infiltrated verrucosus lesion on the anterior aspect of the chest and on the neck. The skin biopsy revealed histiocytes throughout the whole dermis containing thin crystalloid structures in the cytoplasm. Upon histopathological examination, crystal-storing histiocytosis was diagnosed and consequently a hematological examination revealed multiple myeloma IgG Kappa. Skin involvement by CSH proceeded the diagnosis of multiple myeloma by 4 years. CONCLUSIONS: Phagocytosis of crystals of immunoglobulins by histiocytes (crystals storing histiocytosis) is a rare symptom associated most often with lymphoproliferative disease. The clinical picture is not characteristic, in the histopathologic picture it is striking similarity to rhabdomyoma. The skin involvement by crystal storing histiocytosis can be the first symptom of malignant lymphoma that can proceed the hematological malignancy by years.

Incidental granular parakeratosis associated with dermatomyositis.

A 43-year-old patient presented with a 4-month history of intermittently occurring symmetrical and slightly scaling erythematous plaques in his zygomatic regions. Because of polymyositis in the patient's history, the skin lesions were thought to be a manifestation of dermatomyositis. The skin biopsy revealed a sparse superficial perivascular infiltrate of lymphocytes, which was associated with telangiectases and both discrete vacuolar alteration and smudging of the dermal-epidermal junction. These findings were consonant with dermatomyositis. In addition to these features focal granular parakeratosis was present. The histopathologic presence of granular parakeratotic corneocytes above a zone of orthokeratosis and the absence of clinical features of granular parakeratosis indicate the granular parakeratosis is incidental.

Incidental granular parakeratosis associated with molluscum contagiosum.

A patient presented with a 4-month history of slowly progressive pruritic papules on her trunk and extremities. Biopsies from 2 of these lesions revealed molluscum contagiosum. One of the biopsies also showed several small foci of granular parakeratosis. Based on the clinical features and course of this patient, the granular parakeratosis seems to be an incidental finding.

Incidental granular parakeratosis associated with molluscum contagiosum.

A patient presented with a 4-month history of slowly progressive pruritic papules on her trunk and extremities. Biopsies from 2 of these lesions revealed molluscum contagiosum. One of the biopsies also showed several small foci of granular parakeratosis. Based on the clinical features and course of this patient, the granular parakeratosis seems to be an incidental finding.

Segmental pigmented purpura.

A segmental distribution of pigmented purpura (PP) is rare. Our patient presented at 5 years of age with red-brown petechial macules and telangiectases on her chest, the inner and dorsal aspects of the right upper extremity, and the dorsal aspect of the hand, which had developed slowly over the previous 7 months. The lesions were intermittently pruritic. A biopsy from the right arm revealed discrete hydropic degeneration of the basal layer of the epidermis, dilation of the blood vessels, numerous extravasated erythrocytes and lymphocytes, and lymphocytes in the lower part of the epidermis. The skin disease resolved almost completely within 18 months. The general physical examination revealed an open foramen ovale, slight hypogammaglobulinemia (G and A), and enhanced fragility of the blood vessels.