Infiltrative glomus tumor arising from a benign glomus tumor: a distinctive immunohistochemical pattern in the infiltrative component

Malignant glomus tumors (MGT) are rare. Although metastatic MGT has been reported, most MGT have only been locally aggressive, some with multiple local recurrences. We report an additional case of an infiltrative glomus tumor. In addition to the pattern of immunohistochemical staining for alpha-smooth muscle actin (SM-actin) previously described, we performed immunohistochemical stains for Ki-67 and CD34. The infiltrative component of the glomus tumor showed variably decreased staining with SM-actin and occasional tumor cells showed nuclear staining with Ki-67. CD34 staining occurred in stromal cells forming the pseudocapsule in the benign component of this tumor and in other benign glomus tumors. The infiltrative component showed increased CD34 stromal cells. Although Ki-67 staining showed only an occasional proliferative cell, the immunohistochemical staining pattern of CD34 and SM-actin raise the possibility that the infiltrative component of this tumor may have differences in the degree of differentiation from the circumscribed part and that local factors could support its spread from a conventional benign glomus tumor.     

Ectomesenchymal chondromyxoid tumor: histopathologic and immunohistochemical study of two cases without a chondroid component

Ectomesenchymal chondromyxoid tumor (ECT) is a rare benign neoplasm usually affecting the anterior dorsum of the tongue. Histopathologically, it is formed by spindle, round and/or polygonal cells embedded in a chondromyxoid matrix. Immunohistochemical positivity for vimentin, S-100 protein, glial fibrillary acid protein and neuron-specific enolase are helpful to confirm the diagnosis. There are 42 cases of ECT of the tongue reported in the English language literature, three of them showing no chondroid matrix. We describe two additional cases of ECT lacking the chondroid component, exhibiting areas of reticulated myxoid and cellular pattern. Considering the microscopical features, ECT can be classified in classic and 'chondroid-free' variants, the latter including the reticulated myxoid and cellular patterns. It is important to consider that the cellular ECT usually exhibits predominance of an infiltrative atypical cellular component that may mimic a malignant tumor.     

Calcifying aponeurotic fibroma of the knee: A case report with radiological findings

Calcifying aponeurotic fibroma is a rare type of benign tumor that occurs most commonly in the distal extremities of young children. Due to its infiltrative growth, it has a high tendency of recurrence. Although the clinicopathological features of over 100 cases of this rare disease have been reported, its clinical and radiological features have yet to be described in detail. We present a case of calcifying aponeurotic fibroma of the knee from birth with radiological images, that demonstrate the peculiar features of this uncommon benign tumor and discuss its clinicopathological features based on computed tomography and magnetic resonance images.     

A rare case of atypical cellular neurothekeoma in a 68-year-old woman

Cellular neurothekeoma is a benign dermal lesion of uncertain differentiation. The atypical variant of cellular neurothekeoma, characterized by features such as large size, deep penetration, diffusely infiltrative borders, vascular invasion, high mitotic rate and marked cytologic pleomorphism, has been very rarely reported in the literature. We present the clinical, histopathological and immunohistochemical profile of a new case of atypical cellular neurothekeoma in a 68-year-old female patient who was diagnosed with ductal breast carcinoma in situ before. An erythematous painless papule arose in her right breast, and tentative clinical diagnosis was orientated toward skin metastasis of breast cancer or fibroma. Upon histological examination, the lesion showed the histological and immunohistochemical features of atypical variant of cellular neurothekeoma with high mitotic rate, marked cellular pleomorphism and penetration into subcutaneous fat. A further unusual feature in our patient was her age, because she is the oldest patient reported in the literature with diagnosis of atypical cellular neurothekeoma so far. Prognosis remains uncertain because only few cases of atypical cellular neurothekeoma have been reported in the literature, with a very limited follow-up time. Our report contributes to a better characterization of the clinical and morphologic features of atypical cellular neurothekeoma.     

Atypical nevi of the scalp in adolescents

BACKGROUND: A few reports in the literature point out that in special areas of the body, nevi can have peculiar pseudomelanomatous features. In our routine work, we have met few examples of atypical nevi with peculiar features on the scalp of teenagers. To evaluate the frequency and the biological behaviour of these lesions, we have conducted a complete survey on melanocytic lesions on the scalp in a significant group of patients. MATERIALS AND METHODS: Thirty-nine nevi of the scalp were from adolescents (12-18 years), 160 from adults, and 30 from children below the age of 12 years. RESULTS: About 10% of the melanocytic nevi of the scalp of adolescents have atypical cytological and architectural aspects that are different from those seen in Clark's dysplastic nevus. The most striking features were the presence of large bizarrely shaped nests scattered disorderly along the junction with follicular involvement. Other findings were pagetoid spread of cells above the junction and the discohesive pattern of the melanocytes in the nests. Mild cytological atypia was present but less significant. Such distinctive aspects are not found in nevi of the same site in adults or younger children. The general pattern of these atypical nevi of the scalp of adolescents closely recalls that of the so-called atypical nevi on special sites, i.e. nevi on mammary line, genitalia and body's folds. Despite the architectural and cytological atypia, clinical follow-up does not show any tendency to recur or proclivity to malignant behaviour. CONCLUSIONS: Despite their similarities with melanoma, the nevi with atypical features of the scalp of adolescents are probably an entirely benign entity, at least at the moment of their excision. However, although benign, the relationship of this peculiar group of nevi with melanomas developed in adulthood remains entirely unknown, and the complete excision with conservative margins seems a recommendable procedure.     

Atypical neurothekeoma: a new case and review of the literature

Background:  Neurothekeoma is a rare neoplasm ascribed into the broad category of benign peripheral nerve sheath tumors. The atypical cellular variant of this neoplasm, showing a peculiar histological pattern, has been very rarely reported in literature.
Methods:  The clinical, histopathological and immunohistochemical profile of a new case of atypical cellular neurothekeoma in a 32-year-old woman is reported.
Results:  The described neoplasm showed the histological features of atypical variant of cellular neurothekeoma with high-rate mitotic activity and deep penetration into subcutaneous fat.
Conclusions:  Because only few cases of atypical neurothekeoma have been reported in literature, clinical and morphological available data on this neoplasm are very few, and its prognosis remains uncertain; anyway, dermatologists should be aware of histological features of this neoplasm for which a complete surgical excision is recommended.     

A concise review of angiofibroma of soft tissue: A rare newly described entity that can be encountered by dermatopathologists

Angiofibroma of soft tissue (AFST) is a newly described, rare mesenchymal neoplasm with fibroblastic and vascular components; it can be seen in both sexes and in a broad age range. It presents as a slowly enlarging mass, most often in the deep tissues of the upper and lower extremities, but occasionally in a superficial location where it may be encountered by dermatopathologists. It has a benign clinical course with a very low probability of recurrence after complete excision. This lesion has a prominent vasculature and may have an infiltrative growth pattern. These features could lead to a misdiagnosis, such as malignant vascular tumor, by an unwary dermatopathologist. The diagnosis of AFST initially relied solely on morphology and immunohistochemistry but, more recently, molecular studies have begun to play a role. Because of the potential for misdiagnosis, we present this review to raise awareness.     

Atypical pilar leiomyomatosis: an unusual presentation of multiple atypical cutaneous leiomyomas

Cutaneous leiomyomas are relatively common benign smooth muscle tumors that may arise as solitary or multiple lesions. Rare forms with cytologic atypia, and features similar to symplastic leiomyomas of the uterus, have been described. We report a case of multiple cutaneous atypical leiomyomas occurring in a 43‐year‐old man with long history of lesions of the right lower leg and a family history of leiomyomatosis. Twenty of the lesions were excised due to pain and were examined histopathologically. All the lesions exhibited features described in atypical leiomyomas of the skin including increased cellularity, nuclear atypia and pleomorphism, and low mitotic activity. The biologic potential of cutaneous atypical leiomyomas is uncertain. Only a few case reports exist in the literature with the majority occurring as solitary lesions. Most of the reported atypical leiomyomas have behaved in a benign fashion. However, a rare account of transformation to leiomyosarcoma emphasizes the need for long‐term follow up of these patients. Herein, we describe a case of multiple atypical cutaneous leiomyomas arising in the setting of familial leiomyomatosis.     

Dermoscopic patterns of benign volar melanocytic lesions in patients with atypical mole syndrome

BACKGROUND: Acral benign melanocytic lesions in white populations, particularly in subjects with atypical mole syndrome, have been poorly characterized until recently. The advent of dermoscopy has enabled more specific diagnoses of these pigmented skin lesions. OBJECTIVE: To evaluate the clinical and dermoscopic features of benign volar lesions in a group of white patients with atypical mole syndrome. SETTING: A private medical center specializing in early diagnosis of malignant melanoma and a melanoma unit in a university hospital. METHODS: Acral melanocytic lesions in 511 patients with atypical mole syndrome were studied using standard clinical assessment and dermoscopy. RESULTS: Two hundred ten acral melanocytic lesions were observed in 156 of the patients: 165 lesions were present on the soles of 121 patients and 45 lesions on the palms of 35 patients. No acral malignant lesions were detected. We observed the following patterns of lesions: parallel furrow in 111 lesions (52.9%), latticelike in 26 lesions (12.4%), fibrillar or filamentous in 13 lesions (6.2%), and nontypical in 29 lesions (13.8%). In 31 lesions (14.8%), we observed 3 previously undefined patterns: a globular pattern in 11 lesions (5.2%), a homogeneous pattern in 15 lesions (7.1%), and an acral reticular pattern in 5 lesions (2.4%). CONCLUSIONS: We observed a greater number of benign melanocytic lesions in glabrous skin than expected, probably related to our cohort selection of patients with atypical mole syndrome, although the lesions generally exhibited patterns on dermoscopy similar to those seen in Japanese studies. We defined 3 new benign dermoscopic patterns, which will enable better characterization of acral lesions.     

The value of typing basal cell carcinomas in predicting recurrence after surgical excision

A classification, based on growth pattern, was devised and applied to 156 basal cell carcinomas from134 patients. The tumours were divided into four main groups; (i) nodular; (2) nodular with infiltrative margin; (3) infiltrative; (4) multifocal. The infiltrative and multifocal types exhibited a high rate of recurrence following surgical excision whereas recurrence of nodular tumours was much rarer. It is therefore suggested that growth pattern should always be stated in the routine histopathological reporting of these neoplasms. Other features were studied and found to have no prognostic value. These included the various types of epithelial differentiation and such stromal factors as the degree of lymphocyte and plasma cell infiltration and the presence of amyloid or elastic fibres.     

Infantile myofibroma in a prematurely born twin: a case report

Infantile myofibromatosis is a rare benign tumor of infancy and childhood that occurs in solitary, multiple, and generalized forms with similar histology but different clinicopathologic and prognostic implications. Even solitary tumors need follow-up, as the type of presentation will be determined over time. It is necessary to differentiate this entity from other more aggressive tumors, especially rhabdomyosarcoma, which is treated by chemotherapy prior to excision. We describe a prematurely born twin girl who had at birth a solitary tumor of the cervicoscapular region, involving the dermis and subcutis. A fine-needle aspiration biopsy (FNAB) specimen obtained soon after her birth suggested a diagnosis of benign neoplasm. The tumor was excised 1 month later, at which time it was significantly enlarged, ulcerated, and also exhibited worrisome histologic features including mitoses and infiltrative growth. It had the characteristic histologic pattern of infantile myofibromatosis, and myofibroblastic features of tumor cells were confirmed immunohistochemically and ultrastructurally. During the follow-up period of 39 months, there was no sign of recurrence or new tumors.     

Proliferating trichilemmal tumors: clinicopathologic evaluation is a guide to biologic behavior

BACKGROUND: Trichilemmal (pilar) cysts are common skin lesions that usually occur on the scalp of elderly women. They differentiate towards the follicular outer root sheath epithelium and show trichilemmal keratinization. Proliferating trichilemmal tumor (PTT) shows features of typical pilar cyst, but additionally shows extensive epithelial proliferation, variable cytologic atypia and mitotic activity. The malignant potential of PTT is controversial, as only a small number of histologically malignant PTTs and a smaller number of clinically malignant PTTs have been reported. METHODS: We retrieved from our archives five PTTs that deviated from ordinary PTTs with regards to either cytology or architecture. We also reviewed all previous reports of histologically malignant PTTs, with the goal of delineating criteria for the diagnosis of malignant PTTs. RESULTS: Five cases of PTT showing atypical cytoarchitectural features were retrieved from our archives and reviewed with respect to size, growth pattern, cellularity, cytologic atypia, and mitotic activity. The patients (four female, one male) ranged from 54 to 83 (mean 65) years. The tumors measured from 1 to 16 cm in diameter (mean 5 cm) and four out of five occurred on the scalp. All tumors showed at least focal areas of typical PTTs. Three cases were circumscribed but had areas of moderate to focally marked cytologic atypia. Two cases showed infiltrative growth, marked cytologic atypia and mitotic activity. Clinical follow-up was available for four of five cases and ranged from 6 to 84 (median 48) months. Follow-up showed two cases with local recurrence and one case with distant metastasis. This last patient died of disease; all other patients are disease-free. CONCLUSIONS: Review of our cases and the published literature suggests that the diagnosis of malignant PTT be given to PTT showing a combination of non-scalp location, recent rapid growth, size greater than 5 cm, infiltrative growth, and significant cytologic atypia with mitotic activity. At the present time the stratification of malignant PTT into low- and high-grade categories is not possible.     

Dermoscopy

First, a brief introduction about types of dermoscope and an explanation on the theory of dermoscopy are provided. Second, some introduction on the difference of dermoscopic pictures between benign and malignant neoplasm is given. Basically, benign lesions tend to show symmetrical dermoscopic structures and colors, whereas malignant lesions have a tendency to present irregular and atypical dermoscopic structures. Third, the relationship between dermoscopic images and anatomical structures will be shown. Acral melanocytic lesions have site-specific dermoscopic patterns, namely parallel furrow pattern or parallel ridge pattern. These parallel patterns are due to different distribution of benign and malignant melanocytes. Benign melanocytes (nevus cells) are mainly found on the tips of crista profunda limitans and supply melanin granules to the furrows of stratum corneum, making a parallel furrow pattern. To the contrary, melanoma cells proliferate mainly on the tips of crista profunda intermedia or rather diffusely and randomly, and supply melanin granules irregularly and diffusely to the ridges of stratum corneum, having parallel ridge pattern. Fourth, the global features of dermoscopic findings are described respectively with definitions of the technical terms. To analyze dermoscopic structures, it is easier to look at global features first and local features next. Basic global features include reticular, globular, cobblestone, homogeneous, starburst and parallel patterns. If a given dermoscopy image has two patterns, the more prominent pattern might be chosen. If it has more than three dermoscopic patterns, then multi-component pattern is the reasonable selection. If there are no particular dermoscopic structures, then the unspecific pattern will be selected. Finally, some comments on the relationship between dermoscopy and dermatopathology are given briefly. It is always useful to imagine dermatopathological features when examining a dermoscopic image. There are considerable relations between dermoscopy and dermatopathology.     

Primary cutaneous diffuse leiomyosarcoma with desmoplasia

A 65-year-old man presented with an indurated plaque over his left cheek and left neck. An initial punch biopsy of skin showing increased smooth muscle bundles was consistent with a diagnosis of smooth muscle hamartoma. A second incisional skin biopsy revealed a well-differentiated smooth muscle proliferation invading into the dermis and subcutaneous fat in a diffusely infiltrative pattern and with a desmoplastic component, suggesting a diagnosis of desmoplastic leiomyosarcoma. Resection of the tumour confirmed the presence of a cytologically low grade leiomyosarcoma with an insidious infiltrative growth pattern. This rare pattern of diffuse leiomyosarcoma is important to recognize as the histological features are subtle and may potentially constitute a pitfall in histological diagnosis in a small biopsy specimen. In addition, our case illustrates overlapping morphology between diffuse and desmoplastic types of leiomyosarcoma.     

Proliferating trichilemmal cyst: report of two cases,one benign and the other malignant

Proliferating trichilemmal cyst (PTC) is a rare but morphologically distinct tumor that usually arises on the scalp of elderly women. We report two cases of PTC, one benign and the other malignant. PTCs are well circumscribed, subepidermal lesions and demonstrate a uniform histologic pattern with varying degrees of cytological atypia. Malignant proliferating trichilemmal cyst (MPTC) has features in common with benign proliferating trichilemmal cyst (BPTC), including a central area of abrupt keratinization and hyperplastic squamous epithelium forming solid areas. The diagnosis of MPTC is essentially based on histological features. The presence of a high mitotic rate, atypical mitosis, severe nuclear pleomorphism, and tumor invasion of the adjacent tissues are the essential histological features of malignancy in these unusual tumors. The therapeutic approach in malignant cases is the same as that in the treatment of BPTC: surgical removal with a wide clear margin. However, even with adequate resection, both tumors tend to recur locally.     

Microcystic adnexal carcinoma – aggressive infiltrative tumor often with innocent clinical appearance

Microcystic adnexal carcinoma is a rare sweat gland malignancy, characterized by slow, but aggressive infiltrative growth. Histologic characteristics are follicular and glandular differentiation, as well as bland cytologic features. The benign histologic appearance, particularly in the upper level of the tumor, can be confused with syringoma or benign follicular neoplasm. Thus the risk of misdiagnosis is considerable, especially if only superficial biopsies are provided. We report two patients with microcystic adnexal carcinoma, using them as a basis to discuss, pathogenesis, diagnosis, histology and therapy of the tumor.     

Congenital Spitz nevus clinically mimicking melanoma

The differentiation between atypical variants of Spitz nevus and melanoma is often difficult given the many clinical and histopathologic similarities between the two. We report a case of an infant with a congenital scalp lesion exhibiting clinical features of melanoma, including variegation and regression of pigmentation and a rapidly changing appearance. Histologic examination of the excised lesion revealed a benign congenital Spitz nevus. This case emphasizes the need for clinical and histologic correlation in determining the benign or malignant nature of atypical pigmented lesions in infants.     

Oral intramuscular hemangioma: Report of three cases

Intramuscular hemangioma (IMH) represents less than 1% of all hemangiomas. In the head and neck region, it occurs mostly in the masseter, temporalis and sternocleidomastoid muscles. Despite its infiltrative growth pattern and several worrisome histological features, such as increased mitotic activity, plumpness of the nuclei, intraluminal papillary projections or perineural infiltration, the lesion is benign, and complete surgical excision is the preferred treatment for such oral lesions. Herein, we report three rare cases of IMH in the tongue and lip, discuss the clinical and histological aspects, and review the literature regarding this lesion.     

Myoepithelial carcinoma of the retromolar area with extensive mandibular involvement

Myoepithelial tumors were first described in 1943, and account for less than 1% of all salivary gland neoplasms. Their malignant variant, myoepithelial carcinoma, was first reported by Stromeyer et al. in 1975 and represents a very rare entity, characterized by distinct morphologic heterogeneity and an infiltrative growth pattern into adjacent tissues. However, there have been few reports on myoepithelial carcinoma affecting intra‐oral minor salivary glands, and its immunohistochemical features have been poorly illustrated. We herein describe a rare case of myoepithelial carcinoma affecting the retromolar region of a 52‐year‐old woman that caused extensive mandibular bone destruction. We also reviewed the English literature concerning the involvement of intra‐oral minor salivary glands by myoepithelial carcinoma.     

Dermatofibrosarcoma protuberans – An Update

Dermatofibrosarcoma protuberans (DFSP) is a rare fibroblastic skin tumor of intermediate malignancy. Its pathogenesis has not yet been fully clarified. Recent basic genetic research has shown chromosomal translocations, generally termed “ring chromosomes”, in DFSP. These arise from a fusion of chromosome regions 17q22 and 22q13, the gene loci which code the alpha chain of type I collagen. The diagnosis is made histologically. Differentiation from atypical dermatofibroma and dermatomyofibroma, as well as from malignant fibrous histiocytoma, whose prognosis is usually much less favorable, can be improved by immunostaining for CD 34 and Factor XIIIa. The extent of the tumors can be estimated by CT and more precisely with MRI. All these techniques fail to detect the fine tumor fascicles extending into the adjacent connective tissue and fat. Surgery is the therapy of choice for DFSP. The locally infiltrative growth pattern features clinically inapparent extensions which often extend for long distances in a horizontal direction. These tumor extensions are best detected by uninterrupted histological check of all margins, including the base (3‐D‐histology), with paraffin sections. Re‐excision of tumor‐positive areas until tumor‐free margins are obtained (“histographic surgery”) insures a high cure rate (97 %) while preserving normal tissue.