Tumor of the follicular infundibulum with sebaceous differentiation

BACKGROUND: Tumor of the follicular infundibulum (TFI) is a relatively rare tumor which clinically presents as a solitary keratotic papule usually on the head and neck which on microscopic examination typically reveals a plate-like fenestrated epithelial tumor composed of pale staining cells. METHODS: We describe a new variant of TFI. An 80-year-old male with a history of multiple basal cell carcinomas and a squamous cell carcinoma presented with a 2-year history of a red, scaly, slightly elevated plaque on the lateral aspect of his right buttock. RESULTS: Histopathological examination revealed plate-like reticulate epithelial outgrowths of large and pale cells with foci of sebaceous differentiation and numerous colloid bodies. Differential diagnosis included superficial basal cell carcinoma with sebaceous and ductal differentiation, tumor of the follicular infundibulum, an unusual fibroepithelioma of Pinkus or an eccrine fibroadenoma with sebaceous differentiation. CONCLUSION: This case illustrates a hybrid adnexal tumor with histologic features common to both tumor of the follicular infundibulum and superficial epithelioma with sebaceous differentiation.     

Malignant proliferating trichilemmal tumor

Proliferating trichilemmal tumor (PTT) is a benign tumor originating from the outer root sheath of a hair follicle. Malignant transformation in case of PTT is very rare and unusual finding. It is usually confused with squamous cell carcinoma both sharing many common features. So the identification of malignant PTT is very essential. Only 39 well-documented cases of malignant proliferating trichilemmal cyst have been published to date in the English language literature. We hereby present a case of a 75-year-old female patient with a rapidly growing swelling on the scalp.     

Combined malignant melanoma and basal cell carcinoma tumor of the intermingled type

BACKGROUND: The combination of malignant melanoma (MM) and basal cell carcinoma (BCC) within a single tumor is an unusual finding. CASE REPORT: An 84-year-old white man with a pigmented tumor on the back showing a combination of MM and BCC. RESULTS: A 1.5 x 1.5-cm irregular brown lesion on the back was clinically suggestive of MM. Histopathologically, the lesions turned out to be a combined tumor consisting of a superficial BCC and a regressive MM with a tumor thickness of 1.25 mm. The conglomerates of the BCC lay within the MM and were admixed with a high number of Melan-A-positive melanocytic cells. CONCLUSION: By reviewing the low number of published cases, we found that a combined MM-BCC tumor exists in two variants: a collision type in which components of each cell type are clearly demarcated and an intermingled type in which both cell types grow intimately together. Although both types occur as a mere incidence, in particular, the intermingled type may be diagnostically challenging and the evaluation of its dignity may be questionable.     

Eruptive tumors of the follicular infundibulum presenting as hypopigmented macules on the buttocks of two Black African males

We report two cases of eruptive tumors of the follicular infundibulum (TFI) with an unusual clinical presentation which has not been described previously in literature. In both cases, the appearance was strikingly similar, consisting of multiple asymptomatic hypopigmented macules on the buttocks of two Black African males, aged 38 and 55 years old. In both cases, the eruption had evolved over several months. The individual lesions were of similar size, approximately 1 cm, with irregular and ill-defined borders. Histopathological examination revealed a superficial and horizontal plate-like proliferation of keratinocytes emanating from the epidermis with multiple slender attachments. Pale keratinocytes were present within the epithelial plates. A Fontana stain showed a loss of melanin pigment from the epithelial plates. Orcein (elastic) stain highlighted an increase of the number of the elastic fibers surrounding the tumor. On the basis of these findings, a diagnosis of eruptive TFI was established for both cases. Among the various presentations of TFI, only the eruptive variant appears to be clinically distinctive, with asymptomatic hypopigmented macules usually located on the face, neck and upper trunk. Eruptive TFI should also be added to the clinical differential diagnosis of multiple hypopigmented macules on the buttocks of Black patients.     

Infundibular and trichilemmal keratinization of a pilar tumor

Microscopic examination of a cystic epithelial tumor removed from the elbow of a 52-year-old man showed islands of epithelium undergoing keratinization without formation of a visible granular cell layer, as occurs within the follicular isthmus, in trichilemmal cysts, and in pilar tumors (proliferating trichilemmal cysts). Other areas showed keratinization with the formation of a distinct, even prominent, granular cell layer, as seen within the follicular infundibulum and in epidermal cysts. Possible modes of origin and relationships among these tumors and epidermal cysts are presented.     

Ulcus terebrans

Basal cell carcinoma (BCC) is the most common tumor in humans and is defined as a slow-growing, locally invasive, epithelial skin tumor which rarely metastasizes. The first line treatment is surgical excision with histologic examination of the tumor margins, but numerous alternative therapies are available. A 75-year old patient with the most destructive form of BCC, ulcus terebrans, involving the scalp and invading the frontal bone. We discuss the problems and therapeutic limitations for this unusual BCC variant.     

A Case of Tumor of the Follicular Infundibulum with Sebaceous Differentiation

Tumor of the follicular infundibulum (TFI) is an uncommon benign adnexal tumor that usually presents as a solitary keratotic papule on the face or scalp of elderly patients. Histopathologically, it typically manifests as a plate-like fenestrated proliferation of monomorphic pale-staining cells. A 76-year-old male presented with about a 2 cm, well-defined, yellowish to brownish, slightly elevated, twisted and bent, interrupted, cord-like plaque on his left lower abdomen. Microscopic examination revealed a sharply demarcated plate-like proliferation of pale cells localized in the papillary dermis with multiple connections to the overlying epidermis. The histopathological features were compatible with TFI, except for foci of sebaceous differentiation. There has been one previous case report of TFI with sebaceous differentiation in the English medical literature. Herein, we report on a singular case of TFI with sebaceous differentiation.     

Expression of E-Cadherin in Skin Carcinomas

In this study, we investigated the expression of E-cadherin in 31 cases of human skin carcinoma including basal cell carcinoma (BCC), squamous cell carcinoma (SCC), Paget's disease, Bowen's disease (invasive type), and trichilemmal carcinoma, by immunohistochemical staining using a monoclonal antibody specific for E-cadherin. Similar to the E-cadherin expression in normal epidermis, E-cadherin was strongly expressed in all samples of BCC on the cell borders, whereas marked decrease or loss of E-cadherin expression was found in the tumor cells of SCC, Paget's disease, and Bowen's disease (invasive type). On the other hand, E-cadherin expression of trichilemmal carcinoma was slightly reduced. Considering the clinical and histological features of these skin carcinoma, the reduction of E-cadherin expression is considered to be associated with the invasion and metastasis of human skin carcinoma.     

Trichilemmal tumor arising in a seborrheic keratosis: analysis of cell kinetics by BrdU staining.

We report a case of a 74-year-old male with a trichilemmal tumor arising in a seborrheic keratosis on the buttock and the results of a cell kinetic study of this tumor using a BrdU staining method. The incidence of trichilemmal tumor arising in a seborrheic keratosis seems to be extremely rare. The labeling index of this tumor was 12.0%; this was a level intermediate between normal epidermis and a variety of hyperproliferative skin diseases such as squamous cell carcinoma, Bowen's disease, and psoriasis vulgaris. DNA replicating cells were present in the germinative layers in normal epidermis and the benign hyperproliferative skin diseases, psoriasis vulgaris. In contrast, DNA replicating cells were found throughout the entire epidermis in premalignant and malignant tumors such as in Bowen's disease and squamous cell carcinoma. In this case, DNA replicating cells were localized mainly in the basal and parabasal cell layers, but also seen in the upper squamous layers. These findings suggest that this trichilemmal tumor had a malignant tendency, though it was slow-growing and relatively benign in nature.     

Lipomatous mixed tumor of the skin

An unusual tumor of the neck in a 56-year-old female is reported. The tumor was composed of tubules and small cords of epithelial cells dispersed in the fibromyxoid and adipose stroma. At the periphery, the tumor was not encapsulated and its border was intermingled with the subcutaneous fat. Lack of decapitation secretion and the absence of long tubules suggested an eccrine origin; however, in some of the tumor areas, the cells showed brightly eosinophilic copious cytoplasm that may indicate an apocrine differentiation. As an area of chondroid metaplasia was identified, the diagnosis of a mixed tumor was rendered. This unusual type of skin adnexal neoplasm with unique relation of the epithelial component to the surrounding adipose tissue requires differentiation with the primary cutaneous and metastatic carcinomas.     

Cuerno tricolémico: presentación de un nuevo caso y revisión de la literatura

Trichilemmal horn, or trichilemmal keratosis, is an uncommon benign neoplasm of follicular lineage with trichilemmal differentiation.The essential characteristics of this tumor are its clinical presentation in the form of a cutaneous horn with trichilemmal keratinization apparent in the histology study (with a hyperplastic epithelium giving rise to dense, orthokeratotic eosinophilic keratin).We present a new case of this type of tumor in an 82-year-old woman who developed a solitary lesion on her scalp after surgical removal of a trichilemmal cyst. On the basis of the pathology report, the tumor was diagnosed as trichilemmal horn.We review the 33 reports of this tumor in the literature to date.     

Proliferating trichilemmal tumor of the nose

Proliferating trichilemmal tumor is a rare tumor originating in the external root sheath, that is usually found in the scalp of middle-aged or elderly females. Its histologic appearance may not correlate with its clinical behavior. In addition, there are no guidelines available for the treatment of these tumors, making its management a challenge for physicians. We report the case of a 53 year-old woman with a proliferating trichilemmal tumor on her nose, which is a very uncommon location for these lesions.     

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.     

Twist1 in tumor cells and α‐smooth muscle actin in stromal cells are possible biomarkers for metastatic giant basal cell carcinoma

We previously reported a case of giant basal cell carcinoma (BCC) in a 75‐year‐old Japanese man, who subsequently developed a pulmonary metastasis. With regard to the pathogenesis of metastasis of BCC, recently, it has been reported that high levels of expression of Twist1 and N‐cadherin in primary and metastatic tumor cells, suggesting that Twist1 expression and an epithelial–mesenchymal transition (EMT) of tumor cells are important for the promotion of tumor invasion and subsequent metastasis. In this report, we identified the expressions of Twist1 in tumor cells and α‐smooth muscle actin (α‐SMA) in stromal cells in the primary and metastatic sites of giant BCC. These results suggest that Twist1‐induced EMT of tumor cells might have been associated with distant organ metastasis in our case, and the presence of α‐SMA‐positive myofibroblasts surrounding a BCC nest can be one of hallmarks of the aggressiveness of BCC.     

Basal cell carcinoma with prominent central palisading of epithelial cells mimicking schwannoma

Basal cell carcinoma (BCC), the most common malignant neoplasm of skin, may show a wide spectrum of histologic appearances. The presence of peripheral palisades is a very characteristic feature of BCC but, to our knowledge, central nuclear palisading has never been described. We report two cases of BCC exhibiting striking central nuclear palisading with Verocaylike bodies, in a pattern reminiscent of schwannoma. Peripheral palisades and clefts were also present in most tumor nodules and lobules, giving the neoplasms the overall configuration of otherwise typical solid BCC. In addition, foci of conventional BCC could be found adjacent, and in transition, to schwannoid areas. The immunohistochemical study showed strong reactivity for keratins (AE1 and AE3) in tumor cells, whereas no immunostaining for S-100 or muscle-specific actin was found. This previously undescribed histological feature of BCC should lead us to include BCC in the list of tumors to be considered in the differential diagnosis of a cutaneous neoplasm with schwannoid features.     

Proliferating trichilemmal tumor with apocrine sweat glands

A 43-year-old man with a proliferating trichilemmal tumor is described. Since the tumor had appeared on a pre-existing alopecia and accompanied ectopic apocrine sweat glands, it is supposed that the pathogenesis of the tumor of our patient might be similar to that of an organoid nevus.     

Proliferating trichilemmal cyst in an organoid nevus

An unusual tumor mass of the scalp found in an elderly woman is presented. This lesion had many features simulating a verrucous squamous cell carcinoma of the scalp. Pathologic findings eventually revealed the tumor mass to be a proliferating trichilemmal cyst. Differentiation between a benign and malignant process in these lesions can sometimes be difficult. Clinical as well as histopathologic evaluation is necessary to make an accurate diagnosis.     

Trichoblastoma,syringocystadenoma papilliferum,desmoplastic trichilemmoma and tumor of the follicular infundibulum with signet‐ring cells,all arising in nevus sebaceus

Herein, we describe a 63‐year‐old male with multiple tumors arising within a nevus sebaceus on the posterior scalp. On histopathologic examination, four distinct tumors were identified: trichoblastoma, syringocystadenoma papilliferum, desmoplastic trichilemmoma and tumor of the follicular infundibulum (TFI). Within the TFI component of the nevus sebaceus, there was intracytoplasmic accumulation of eosinophilic keratin, as shown on pancytokeratin‐stained sections, imparting a signet‐ring appearance to the cells. To our knowledge, this is the first report of signet‐ring cells arising within a TFI occurring in a nevus sebaceus. We discuss this case as well as review the literature on multiple tumors arising within nevus sebaceus and signet‐ring cell changes in primary cutaneous tumors.     

Cutaneous mixed tumor with lipomatous stroma

Aim:  Mixed tumors are usually composed of two components, one epithelial and the other mesenchymal. The latter component is commonly myxoid or myxochondroid; a massively lipomatous stroma is very unusual. To date, only two cases of mixed tumor of the skin have been reported with this type of stroma.
Methods and results:  We report the case of a 61-year-old man with a mixed tumor situated on the hand, an unusual site for these tumors, with over 90% of the tumor composed of adipose tissue. The tumor was a well-circumscribed, 4.5-cm mass, with the gross appearance of a lipoma. The lipomatous stroma contained nests and ribbons of epithelial cells, with occasional tubular structures, surrounded by a scarce amount of fibromyxoid tissue. Immunohistochemical study showed findings similar to those seen in classic mixed tumors.
Conclusion:  Together with a few other cases in the skin and parotid gland, this report shows how massive adipose differentiation can arise in a mixed tumor of the skin.     

Epithelioid sarcoma with angiomatoid features: report of an unusual case arising in an elderly patient within a burn scar

Epithelioid sarcoma (ES) is a rare, aggressive soft tissue tumor with a characteristic predilection for adolescents and young adults, and a tendency to occur on distal extremities. We report a case of ES arising in an 80-year-old woman within a burn scar that histopathologically showed unusual 'angiomatoid' features. The patient presented initially with a solitary nodule on her right wrist arising at the site of a burn scar. Histopathologically, the tumor was composed of a proliferation of relatively bland, epithelioid and spindle cells focally arranged in a nodular pattern around areas of 'geographic' necrosis. In addition, there were prominent foci of hemorrhage and blood-filled spaces as well as tumor cells with intracytoplasmic vacuoles, features suggestive of an angiomatous process. Immunohistochemistry showed positivity of tumor cells for cytokeratins and epithelial membrane antigen (EMA) whereas all vascular markers tested were negative. The overall histopathologic features were consistent with a diagnosis of ES. Follow up showed multiple recurrences arising proximally along the right upper extremity. Our case underlines the clinical and histopathological heterogeneity of ES, emphasizing the unusual occurrence of ES with 'angiomatoid' features in the elderly. In this uncommon setting, this tumor should be especially distinguished from epithelioid hemangioendothelioma and epithelioid angiosarcoma. The significance of development of ES on a healed burn scar is uncertain, but may suggest a possible causal relationship.