Malignant melanoma arising from a congenital pigmented naevus in a patient with sarcoidosis: cause or coincidence?

A case is described of a 40-year-old man who developed sarcoidosis and at the same time malignant change in a congenital pigmented naevus of his foot. It is proposed that the sarcoidosis may have acted as a predisposing cause of the melanoma in this case. The difficulties of diagnosis and management of patients with coexistent malignant melanoma and sarcoidosis are discussed.     

Onychomycosis with onychodystrophy or acrolentiginous melanoma with onychomycosis and onychodystrophy?

A 68-year-old female patient had been treated locally and systemically for onychomycosis of the left thumbnail for 1 year. During the course of treatment there was increasing destruction of approximately 50% of the nail without Hutchinson's sign. Dermoscopically there were yellow to brown vertical stripes of varying width in the remaining parts of the nail. In the visible nail matrix reddish, brownish and grey-black colored components with varying differential structures could be detected. An acrolentiginous melanoma with a diameter of 1.04?mm could be identified histologically and the associated onychomycosis was confirmed by culturing.     

A case of pachyonychia congenita with unusual manifestations: an unusual type or a new syndrome?

A 30‐year‐old man presented with lesions on his oral mucosa and soles. There were no similar complaints in his family members. The dermatological examination revealed follicular hyperkeratosis on his trunk and upper extremities and flesh‐colored, firm cystic lesions on his axillae. He had focal, painful, hyperkeratotic areas sited particularly on both his soles and palms. In addition to these, leukokeratosis and ulcerative areas on buccal, labial mucosa, tongue, and at corners of the mouth, and complete loss of teeth was observed. The proximal layering was revealed on all of his nails. The laboratory investigations produced normal results except the deficiency of immunoglobulin A. The psychiatric examination revealed mild mental retardation. Keratin gene (KRT6a, KRT6b, KRT16, and KRT17) mutations for pachyonychia congenita were negative. He got removable dental prosthesis because of inadequate alimentation. Squamous cell cancer developed on lower lip mucosa during follow‐up. We present an individual who had different nail dystrophy, epidermal cysts, mental retardation, blepharitis, complete loss of teeth, and negative keratin gene mutations for pachyonychia congenita and developed squamous cell cancer on the oral leukokeratosis lesions. We think that the present case may be an unusual new type of pachyonychia congenita.     

Pleomorphic spindle cell dermal neoplasm with dot‐like keratin reactivity: keratin‐positive AFX or carcinoma?

Atypical fibroxanthoma (AFX) is an uncommon cutaneous neoplasm of pleomorphic myofibroblast‐like cells. Diagnosis requires exclusion of other undifferentiated spindle and pleomorphic cell neoplasms by immunohistochemistry. We report two patients with p63‐non‐reactive spindle cell neoplasms which resembled AFX but demonstrated anomalous dot‐like immunolabeling with antibodies to high molecular weight keratin and keratin 5. One case recurred locally, suggesting such lesions may behave aggressively. Whether these lesions represent keratin‐positive dermal sarcomas or poorly differentiated carcinomas is debatable. Regardless of exact classification, our experience suggests such cases should be managed as high‐risk non‐melanoma skin cancers.     

Spitz nevus or melanoma?

Spitz nevi are benign melanocytic neoplasms of children and young adults that can be exceedingly difficult to distinguish from malignant melanomas. Although a nearly definite diagnosis can be made in most cases, the histological distinction between Spitz nevi and melanomas is equivocal in about 6% to 8% of cases. In those cases, and perhaps even with presumed benign Spitz nevi, clear surgical margins are desirable. The most helpful differentiating features of Spitz nevi are patient age, sharp demarcation, symmetry, maturation of melanocytes at the base, and epithelial hyperplasia. None of these criteria are completely reliable, and multiple other criteria must be considered as well.     

Diagnosis: atypical fibroxanthoma or not? Evaluating spindle cell malignancies on sun damaged skin: a practical approach

Poorly differentiated spindle cell malignancies on sun damaged skin frequently pose a diagnostic challenge for dermatopathologists. The vast majority of these neoplasms ultimately are diagnosed as either atypical fibroxanthoma (AFX), spindle cell squamous cell carcinoma (SCSCC), or spindle cell melanoma (SCM), and rarely leiomyosarcoma or angiosarcoma. Light microscopic clues may suggest one of these neoplasms, but subtle and overlapping characteristics often render precise diagnosis impossible based on morphological features alone. Immunohistochemistry therefore is necessary to firmly and accurately diagnose the majority of spindle cell malignancies on sun damaged skin. We summarize typical clinical and histological findings associated with this group of malignancies and offer a practical immunohistochemical approach to use in their diagnosis.     

Indeterminate cell histiocytosis: fact or fiction?

Abstract: Indeterminate cell histiocytosis is a rare disorder, in which the predominant cells have the characteristics of both Langerhans cells and macrophages. We, in this study, describe 18 patients and compare them with those previously published. Most patients were adults with either solitary or multiple red‐brown papules or nodules. While most lesions were confined to the skin, both conjunctival and bony involvement was seen. Histologically, the lesions showed patterns resembling those described for xanthogranulomas, with predominantly oncocytic (nine patients), spindled (five patients), scalloped (two patients) or vacuolated (two patients) macrophages. The accompanying infiltrate was mainly lymphocytic, although eosinophils and occasionally plasma cells were seen. All lesions were positive for macrophage markers, such as KP1 (CD68) and Ki‐M1p, as well as for S‐100 protein and showed variable reactivity for CD1a. No Birbeck granules were seen ultrastructurally in one patient. Some patients shared features with sinus histiocytosis with massive lymphadenopathy. It is unclear whether this disorder is a separate entity or represents various macrophage disorders identified at various time points in the inflammatory response.     

Becker's naevus and segmental naevus depigmentosus: An example of twin spotting?

A 12-year-old girl presented with a 1-year history of a Becker's naevus involving the right posterior thigh and gluteal area. In addition, three hypopigmented macules of naevus depigmentosus distributed in a segmental pattern on the medial aspect of the right posterior thigh had been present since birth. We suggest that their unusual coexistence in close proximity may represent an example of twin spotting.     

Multiple mucinous and lipomatous variant of eccrine angiomatous hamartoma associated with spindle cell hemangioma: a novel collision tumor?

Eccrine angiomatous hamartoma (EAH) is a rare, benign condition characterized histologically by increased numbers of eccrine elements, as well as numerous capillary channels. In most cases, EAH arises as a single lesion; however, multiple variants have been reported. We report a 35-year-old female patient with multiple, sudoriparous, subcutaneous nodules on the right foot, which showed typical histopathological findings of EAH, and vascular components of the tumor consisted of thin-walled dilated vascular spaces intermixed with spindle cells and some histiocytoid endothelial cells representing spindle cell hemangioma (SCH). To our knowledge, the co-existence of EAH with SCH is a novel finding and not yet described.