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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

From a series of 75 cases of mixed spindle cell and epithelioid cell nevi, 14 were designated as desmoplastic nevi. Junctional activity, theque formation, and pigmentation were uncommon features. As a result, desmoplastic nevi may be confused with a variety of fibrohistiocytic lesions. Well defined intranuclear invaginations of cytoplasm occurred in 12 cases, and were helpful in differentiating desmoplastic nevi from these lesions. Desmoplastic malignant melanoma must also be considered in the microscopic differential diagnosis, but distinguishing features of desmoplastic melanoma include the presence of preexisting lentiginous melanoma, and necrosis of tumor cells and collagen. Desmoplastic nevus was compared to the ordinary variants of mixed spindle cell and eipthelioid cell nevus in an attempt to define etiologic factors responsible for a desmoplastic reaction. No satisfactory explanation could be found since the clinical variables examined were not statistically different.
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PMID:Desmoplastic nevus: a distinct histologic variant of mixed spindle cell and epithelioid cell nevus. 739 26

The diagnosis of malignant melanoma requires clinical recognition of suspect lesions, biopsy, and histologic examination. Histological features which serve to distinguish malignant melanoma from their benign counterparts can be found in both the epidermis and dermis. The intraepidermal component of a common acquired nevus usually consists of more or less uniform theques of melanocytes located at or near the tips of rete ridges. Most melanomas are characterized by less orderly intraepidermal growth with areas in which melanocytes lose their nesting characteristics and are distributed more diffusely, sometimes replacing the basal keratinocytes by confluent growth and sometimes by invading upwards either as single cells or small nests into the upper reaches of the epidermis. Nested melanocytes can be found along the basal layer in malignant melanoma, but these nests are usually quite variable in size and location with respect to the tips of the rete ridges, and they are often irregularly distributed along the breadth of the lesion. The dermal component of malignant melanoma usually shows little tendency towards maturation, unlike that of benign nevi. Mitotic figures are unusual to find in the dermal component of common acquired nevi. When they are present, the possibility of melanoma should be considered. Other cytological features can also be useful in the diagnosis of malignant melanoma, particularly when there is marked cytological atypia; however, in some lesions, the cytological changes are not so pronounced and correct diagnosis depends on evaluation of growth pattern. While distinguishing between melanoma and atypical moles can be difficult, problems also arise in distinguishing melanoma from other neoplastic processes. The most common differential diagnosis includes melanoma, paget's disease, and pagetoid Bowen's disease. Desmoplastic melanoma is frequently difficult to distinguish from spindle cell squamous cell carcinoma and atypical fibroxanthoma. Histochemical and immunocytochemical stains are useful in resolving these problems. The pathology report of a melanoma should include the diagnosis, the maximum thickness of the tumor, the adequacy of the surgical margins (if the lesion has been excised), the presence or absence of ulceration, tumor regression, angiolymphatic invasion, and satellitosis. The inclusion of patients in treatment protocols may require additional information such as the host response of tumor-infiltrating lymphocytes, mitotic index, and Clark's level of invasion.
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PMID:Melanoma: criteria for histological diagnosis and its reporting. 897 May 88

Desmoplastic (sclerotic) nevus, a benign melanocytic neoplasm characterized by predominantly spindle-shaped nevus cells within a fibrotic stroma, can be confused with fibrous lesions and other melanocytic proliferations, including desmoplastic melanoma. We compared the histologic and immunohistochemical features of 16 desmoplastic nevi, nine desmoplastic melanomas, four hypopigmented blue nevi, and six dermatofibromas. The similarities between desmoplastic nevi and dermatofibromas included epidermal hyperplasia (12 of 16), presence of keloidal collagen (15 of 16), hypercellularity (16 of 16), and increased numbers of factor XIIIa-positive dendritic cells (12 of 12). The absence of adnexal induction (0 of 16), the rarity of lesions with multinucleated cells (3 of 16) or epidermal hyperpigmentation (2 of 16), and the presence of S-100 immunoreactivity (16 of 16) and melanocytic proliferation (9 of 16) helped differentiate desmoplastic nevi from dermatofibromas. The similarities between desmoplastic nevi and desmoplastic melanomas included the presence of atypical cells (16 of 16) and HMB-45 expression in the superficial portion of the lesions (11 of 16). The infrequent location on the head or neck (1 of 16), the absence of mitotic figures (0 of 16), a significantly lower number of Ki-67-reactive cells, and a decrease in HMB-45 expression in the deep area of the lesions (8 of 11) helped distinguish desmoplastic nevi from desmoplastic melanoma. Desmoplastic nevi had overlapping features with hypopigmented blue nevi, but features tending to favor the latter included a predominance of ovoid nuclei, higher numbers of atypical cells, and homogeneous staining with HMB-45. We conclude that a combination of histologic and immunohistochemical criteria facilitates the reliable diagnosis of desmoplastic nevus from its simulators.
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PMID:Desmoplastic (sclerotic) nevus: an underrecognized entity that resembles dermatofibroma and desmoplastic melanoma. 1040 1

Desmoplastic/spindle cell melanoma is a rare variant of melanoma. A number of factors complicate the diagnosis of desmoplastic/spindle cell melanoma, including the variable absence of a lentiginous component, its spindle cell morphology, and its many morphologic mimics, including scars, malignant peripheral nerve sheath tumor, neurofibroma, atypical fibroxanthoma, and spindled carcinoma. The immunohistochemical confirmation of desmoplastic/spindle cell melanoma may also be difficult, because the majority of tumors are negative for specific melanocytic markers such as HMB-45 and Melan-A, despite their usual expression of S-100 protein. Two new and potentially promising melanocytic markers, microphthalmia transcription factor (MiTF) and melanoma cell adhesion molecule (Mel-CAM), have been shown to be sensitive markers of epithelioid melanoma, but have not been tested in desmoplastic/spindle cell melanoma or in other rare melanocytic neuroectodermal tumors such as clear cell sarcoma. We immunostained 79 tumors (20 desmoplastic/spindle cell melanomas, 10 scars, 10 neurofibromas, 12 malignant peripheral nerve sheath tumors, 10 atypical fibroxanthomas, 10 clear cell sarcomas, 3 melanotic schwannomas, and 4 cellular blue nevi) for MiTF and Mel-CAM. MiTF expression was seen in 11 of 20 desmoplastic/spindle cell melanomas, 0 of 10 scars, 2 of 10 neurofibromas, 0 of 12 malignant peripheral nerve sheath tumors, 1 of 10 atypical fibroxanthomas, 7 of 10 clear cell sarcomas, 3 of 3 melanotic schwannomas, and 3 of 4 cellular blue nevi. Mel-CAM expression was present in 14 of 17 desmoplastic/spindle cell melanomas, 0 of 10 scars, 4 of 10 neurofibromas, 3 of 11 malignant peripheral nerve sheath tumors, 0 of 10 atypical fibroxanthomas, 9 of 10 clear cell sarcomas, 3 of 3 melanotic schwannomas, and 0 of 4 cellular blue nevi. MiTF and Mel-CAM were coexpressed in 6 of 17 desmoplastic/spindle cell melanomas and in no other tumor. Regarding desmoplastic/spindle cell melanoma, scar, neurofibroma, malignant peripheral nerve sheath tumor, and atypical fibroxanthoma, the sensitivity and specificity of MiTF for desmoplastic/spindle cell melanoma were 55% and 91%, respectively. For this same group of tumors, Mel-CAM had a sensitivity of 82% and a specificity of 83%. We conclude that the sensitivity and specificity of MiTF for desmoplastic melanoma equals or exceeds that of such markers as HMB-45 or Melan-A, and that MiTF should be part of the initial immunohistochemical panel for the work-up of such cases. Mel-CAM, while very sensitive, is relatively nonspecific, because it is also expressed in a variety of mesenchymal tumors and carcinomas. Mel-CAM is best reserved for cases morphologically suspected to be desmoplastic/ spindle cell melanoma, in which S-100 is positive and MiTF and other melanocytic markers are negative. These markers may also be helpful in certain other differential diagnoses, such as distinguishing clear cell sarcomas from epithelioid malignant peripheral nerve sheath tumors.
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PMID:Microphthalmia transcription factor and melanoma cell adhesion molecule expression distinguish desmoplastic/spindle cell melanoma from morphologic mimics. 1114 52

Proteus syndrome is a rare, sporadic disorder that causes postnatal overgrowth of multiple tissues in a mosaic pattern. Characteristic manifestations include: overgrowth and hypertrophy of limbs and digits, connective tissue nevus, epidermal nevus and hyperostoses. Various benign and malignant tumors and hamartomas may complicate the clinical course of patients with the syndrome. Commonly encountered tumors include hemangiomas, lymphangiomas and lipomas. Tumors of the genital tract occur less often. Bilateral ovarian cystadenomas are regarded as having diagnostic value in Proteus syndrome when occurring within the first two decades of life. We describe a 3-year-old girl with Proteus syndrome who developed bilateral paraovarian villoglandular endometrioid cystadenomatous tumors of borderline malignancy (low malignant potential) of the broad ligament. Desmoplastic tumor implants, presumably noninvasive, were present in biopsies from the pelvic floor, cul-de-sac and omentum. This is the first recognized example of a cystic borderline epithelial tumor of the female genital tract and the first paraovarian tumor reported in a patient with Proteus syndrome. Previously reported tumors and cystic lesions involving the female genital tract and the male genital tract in patients with Proteus syndrome are reviewed. We suspect that specific testicular and paratesticular tumors may prove to have the same diagnostic value in Proteus syndrome as do bilateral cystic ovarian and paraovarian tumors.
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PMID:Genital tract tumors in Proteus syndrome: report of a case of bilateral paraovarian endometrioid cystic tumors of borderline malignancy and review of the literature. 1185 May 47

Desmoplastic melanoma (DM) is a fibrosing variant of spindle cell melanoma. It most often presents as an indurated lesion in chronically sun-damaged skin. Due to the lack of characteristic clinical features, early detection is uncommon. At the time of excision, the tumors usually extend into the reticular dermis or deeper. DM is prone to misdiagnosis. It may simulate histologically sclerosing melanocytic nevi as well as various benign and malignant nonmelanocytic lesions. There is significant morphologic variability among tumors classified as DM. Desmoplasia may be prominent throughout the entire tumor ("pure" DM) or represent a portion of an otherwise nondesmoplastic melanoma ("combined" DM). Some tumors show neuroma-like features with prominent nerve involvement, in which case the term "desmoplastic neurotropic melanoma" is used. Immunophenotypically, DMs are usually strongly and homogeneously positive for S-100 protein but are often negative or only focally positive for melanocyte differentiation antigens such as tyrosinase, gp100, Melan-A, and microphthalmia transcription factor. DM differs from conventional melanoma in its clinical course. It is associated with a higher tendency for local recurrence, but metastases to regional lymph nodes are less common. Evidence is also emerging that for patients with thick melanomas, the presence of a paucicellular fibrosing tumor histology (pure DM) is a favorable prognostic factor for survival.
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PMID:Cutaneous desmoplastic melanoma. 1573 77

Desmoplastic hairless hypopigmented nevus (DHHN) is the name Ruiz-Maldonado et al. gave to a new variant of giant congenital melanocytic nevus characterized clinically by a hard ligneous consistency, absence of hair and progressive loss of pigment. Histologically, dermal fibrosis consistent with desmoplasia is a predominant feature. We describe a 6-year-old boy with a hard hairless pigmented congenital nevus involving the lumbosacral area, buttocks, perineum and scrotum. During the first years of life, the nevus showed a progressive reduction in colour, size and consistency. These changes continued until the age of four when a well-demarcated tumour appeared, within the nevus, on the right buttock. Resection of this outgrowth was performed. Histologically, nevus cells of normal appearance between thick collagen bundles were present. Immunostaining revealed S100 +, Vim +, HMB45--results. The nevus has continued to involute to date. An immune response against the melanocytes of the nevus may explain this type of evolution.
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PMID:Desmoplastic hairless hypopigmented nevus (DHHN). A distinct variant of giant melanocytic nevus. 1628 Feb 97

Desmoplastic hairless hypopigmented nevus is an extremely rare sclerotic, alopecic, and progressively hypopigmented giant congenital melanocytic nevus, which is histologically characterized by an intense desmoplasia. A significant trend toward spontaneous involution has been described. We report a case of desmoplastic hairless hypopigmented nevus that underwent a progressive depigmentation associated with loss of its woody consistency. The loss of induration appears to be the main marker for the complete regression of these nevi.
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PMID:Desmoplastic giant congenital nevus with progressive depigmentation. 1709 64

Hypopigmented and achromatic melanocytic tumors with spindle cells represent a diagnostic challenge. Spindle cell nevi resemble neural tumors. Desmoplastic nevi imitate dermatofibromas. Hypopigmented and amelanotic blue nevi are variants of the common and cell-rich blue nevus with an enhanced difficulty to make a correct diagnosis due to the lack of pigment. All of the above benign melanocytic tumors with proliferations of hypopigmented spindle cells can more or less show aspects of desmoplastic melanoma. The differential diagnosis of these entities demands a combination of clinical and histological parameters as well as supporting immunostaining. Regarding desmoplastic melanoma, diagnoses frequently made are benign spindle cell neoplasms, scar or unspecific inflammatory condition. As the histological aspects can be so misleading, attention is necessary in order to make the correct diagnosis. Particular care must be taken to rule out desmoplastic melanoma in the case of spindle cell proliferations, a cicatricial or inflammatory process in the classical settings of face, volar skin, or mucous membranes. The spindle cell melanoma must be distinguished from other types of malignant spindle cell neoplasms, which can involve the skin. The differential diagnosis with such tumors is entrusted mainly to immunostaining.
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PMID:[Hypopigmented melanocytic tumors with spindle cells. A review]. 1785 62

Desmoplastic spitz nevus (DSN) is an uncommon melanocytic lesion. The histologic features of this benign tumour may mimic those of certain benign (dermatofibroma and desmoplastic cellular blue nevus) or malignant (metastatic carcinoma and malignant melanoma) neoplasms. We report the case of a male with a DSN, and also review the clinical characteristics, histologic features and differential diagnosis of this extremely rare lesion. The lesion is identified as an asymptomatic reddish-brown dome-shaped papule on the forearm. Microscopic examination showed a symmetric lesion in the dermis. The neoplastic cells were large and epithelioid-shaped, and were either isolated as individual cells or arranged in small nests in a paucicellular hyalinized stroma. Nuclei were large and vesicular with small nucleoli and no mitoses. Diffuse expression of S100 and the absence of staining with antibodies to melan-A and HMB45 was observed. A diagnosis of DSN with free margins was made. The histologic presentation of this benign lesion mimics both benign and malignant neoplasms. The immunohistochemical profile (S100 positive, HMB-45 negative and cytokeratin negative) may be helpful to differentiate it from other lesions.
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PMID:Desmoplastic spitz nevus: report of a case and review of the literature. 1884 24


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