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.     

Superficial epithelioma with sebaceous differentiation

Five cases of superficial epithelioma with sebaceous differentiation (SESD) are reported. They occurred as solitary papules on the face of 5 patients, aged 57 to 72. The tumor is characterized by a superficial platelike proliferation of basaloid to squamoid cells with broad attachments to the overlying epidermis. Clusters of mature sebaceous cells are present within the tumors. None of the tumors have recurred or spread following simple excision. SESD is a non-aggressive tumor of uncertain histogenesis with a tendency toward sebaceous differentiation.     

Metastasizing adenocarcinoma and multiple neoplastic proliferations arising in a nevus sebaceus

Nevus sebaceus of Jadassohn is a hamartoma of multiple skin structures. Many neoplasms have been reported to arise in association with nevus sebaceus, most commonly trichoblastoma/basal cell carcinoma and syringocystadenoma papilliferum. We report a case of a 66-year-old woman with an adenocarcinoma as well as multiple neoplastic proliferations arising in a long standing nevus sebaceus on the scalp, with subsequent occipital neck metastatic disease. On histologic evaluation, the epidermis showed changes reminiscent of tumor of the follicular infundibulum as well as basaloid proliferations resembling superficial trichoblastoma. A focus suggestive of syringofibroadenoma was also present. A small dermal collection of basaloid and more mature sebocytes was consistent with a sebaceoma/sebaceous epithelioma. Most of the lesion was composed of an adenocarcinoma with areas showing ductal differentiation with decapitation secretion, well-formed papillae and focal cribriform structures. Other portions demonstrated a high-grade neoplasm with prominent nuclear atypia and a solid pattern of growth resembling high-grade breast carcinoma. Anti-epithelial membrane antigen strongly labeled tumor cells and highlighted ductal structures. Less than 1% of cells expressed progesterone or estrogen receptors. Her2/neu reactivity was focally present, showing 1+ membranous reactivity in 10% of cells. Anti-p63 labeled basaloid cells surrounding the tumor lobules. A breast primary was ruled out by clinical and radiologic examination. This report illustrates an extraordinary case of adnexal neoplasia displaying various lines of differentiation arising in association with nevus sebaceus.     

Localized basaloid follicular hamartoma.

We report a 39-year-old Japanese woman with a 30 x 10 mm, skin-colored, soft, hairless, irregularly elevated plaque in the left retroauricular area. Histologically, it consistently showed features of atypical hair follicles; some showed immaturely developed basaloid epithelial islands invaginated with condensed stromal cells, and others were replaced or associated with solid strands, branching cords, or lace-like networks of undifferentiated basaloid cells. Although the clinical appearance of a typical localized basaloid follicular hamartoma is a plaque of alopecia, this case seems to be a variant, because the histological findings are so characteristic of the entity. The relationship of basaloid follicular hamartoma to other hair-follicle derived tumors is also considered.     

Extraocular sebaceous carcinoma accompanied by invasive squamous cell carcinoma: The first case report and consideration of histogenesis

A 61‐year‐old man presented with a dome‐shaped nodule, 1.2 cm in size, with a central crater covered by keratinous material near the left lateral malleolus. Histological findings demonstrated a basophilic circular cone in the center, surrounded and sharply demarcated by a broad eosinophilic area. The central conical mass was composed mainly of atypical basaloid cells intermingled with scattered atypical sebaceous cells with scalloped nuclei and microvesicular cytoplasms, suggesting sebaceous carcinoma. The peripheral area consisted of atypical keratinizing squamoid cells without sebaceous cells, suggesting invasive squamous cell carcinoma. Atypical sebaceous cells were positive for adipophilin. Atypical basaloid cells were positive for 34βE12 and CAM5.2. Peripheral squamoid cells were positive for 34βB4 and 34βE12 throughout, and were positive for LHP1 in the superficial layer. We herein describe the first case of extraocular sebaceous carcinoma accompanied by invasive squamous cell carcinoma, which might have arisen from biphasic differentiation of cancer stem cells.     

Cutaneous lymphadenoma with ductal differentiation

Cutaneous lymphadenoma (CL) is a recently described neoplasm of unknown histogenesis. Histologically, these tumors typically present as well-circumscribed nodules with scant or no epidermal connections. They are composed of multiple rounded lobules of basaloid cells with some degree of peripheral palisading. These epithelial lobules characteristically show a dense lymphoid infiltrate within them. In cases of CL previously described, there was no obvious adnexal differentiation except for isolated cells showing apparent sebaceous differentiation or hints of follicular differentiation. We report two typical cases of CL that were studied histologically and immunohistochemically. In some of the tumor lobules, there were foci of ductal differentiation, with luminal positivity for CEA and EMA. We postulate that some CL represent a form of immature sweat gland tumor with ductal differentiation.     

Basal cell carcinomas in association with basaloid follicular hamartoma

We describe a unique case of various types of basal cell carcinoma (BCC) associated with basaloid follicular hamartoma (BFH) in a 56-year-old female patient. The lesion consisted of a dark brown and elastic soft nodule and papules within the area of a birthmark on the neck. The lesion was surgically excised. Histological examination of the nodular region revealed aggregations of neoplastic basaloid cells. We diagnosed the nodule as BCC with a racemiform or reticular pattern. In addition, a specimen taken from brownish black papules within the birthmark was found to be composed of anastomosing cords of basaloid cells accompanied by infundibular cystic structures. These features were consistent with an infundibulocystic BCC. In contrast, specimens from a hamartomatous plaque showed distinctive branching strands of basaloid cells that are suggestive of BFH. Therefore, our findings indicate that several types of BCC may develop within a BFH.     

Basal cell carcinoma with matrical differentiation.

Three cases of basal cell carcinoma showing shadow cells within basaloid islands have been described using the term basal cell carcinoma with matrical differentiation for this histologic variant. We present four new cases of basal cell carcinoma with evidence of matrical differentiation. Unlike the cases previously published, these lesions showed nests of shadow cells either within the lobules of basaloid cells or forming nests in the stroma. We also noted the presence of a foreign body reaction and calcification. These neoplasms illustrate the capability of basal cell carcinoma to differentiate toward hair matrix cells. Basal cell carcinoma with matrical differentiation must be added to the uncommon variants of basal cell carcinoma showing adnexal differentiation. A parallel between the degrees of differentiation of the cutaneous sebaceous neoplasms with those showing matrical differentiation is proposed.     

A tumor with sebaceous differentiation showing intraepidermal epithelioma

A sixty-year-old woman had a small papule within a plaque on the left arm. Histologically, the papule was similar to irritated seborrheic keratosis or inverted follicular keratosis and the plaque was intraepidermal epithelioma. However, both lesions included mature sebaceous cells showing sebaceous differentiation. This tumor may be closely related to the pilo-sebaceous unit or sebaceous gland. To our knowledge, no similar tumor has been reported in the literature.     

Sebaceous Epithelioma

An 83-year-old woman had developed an asymptomatic, yellowish, dome-shaped skin tumor on her scalp which had enlarged for a period of 60 years to 10 times 10 times 10 mm in size. Histopathologically, the tumor consisted of undifferentiated basaloid cells, differentiated sebaceous cells and transitional cells. Although the basaloid cells resembled those of basal cell epithelioma (BCE), the tumor was distinct from BCE in the following points; existence of cystic spaces, no peripheral palisading, no proliferation of connective tissue stroma, and no tendency toward local invasion. Immunohistochemical studies using antikeratin monoclonal antibodies revealed that the tumor contained both the keratin types of BCE and of sebaceous glands. Electron microscopically, the tumor cells contained lipid droplets and keratohyaline granules in their cytoplasm. It is suggested that “sebaceous epithelioma” is a benign skin tumor which may be distinguished cytologically from BCE.     

Trichoblastic neoplasm with apocrine differentiation

Trichoblastoma is a benign neoplasm with primitive hair follicle differentiation. The tumor is characterized by nests and cords of epithelial cells in an organized relation to stroma. The epithelial cells differentiate toward follicular germ and follicular sheath. More divergent differentiation in the form of sebaceous elements in trichoblastoma has infrequently been reported in the literature. We report a trichoblastic neoplasm showing typical features of trichoblastoma as well as areas of apocrine differentiation. The neoplasm, which was present for several months, was removed from the chin of a 31-year-old woman. Histologic examination showed a neoplasm composed of basaloid nests with occasional papillary mesenchymal bodies as well as ducts and glands exhibiting apocrine differentiation. Trichoblastoma with apocrine features is rarely reported in the literature.     

Sebaceous carcinoma with apocrine differentiation

A 54-year-old male had a dome-shaped and skin-colored nodule on his nose. Histopathologically, we diagnosed this neoplasm as a low-grade sebaceous carcinoma rather than a sebaceoma based on the scanning magnification and cytology. This low-grade sebaceous carcinoma was associated with glandular structures. We regarded the glandular structures as those of apocrine glandular differentiation based on 1) the histopathologic features of the glandular structures formed by columnar luminal cells with evidence of decapitation secretion; 2) the expression of cytokeratin (CK) 19, CK8, CK8/18, and CK7 in the luminal cells; 3) the positive reaction of carcinoembryonic antigen and epithelial membrane antigen on the luminal surface and in the cytoplasm of the luminal cells; and 4) the common embryologic origin of the folliculosebaceous-apocrine unit. We found CK15 expression in undifferentiated cells within the mantles of normal hair follicles, suggesting that sebaceous stem cells might exist in mantles as follicular stem cells exist in bulge areas. Pluripotent stem cells in the folliculosebaceous-apocrine unit can give rise to follicular stem cells, sebaceous stem cells, and apocrine stem cells. Our patient's neoplasm showed apocrine glandular differentiation and partial immunohistochemical positivity for CK15 in the neoplastic aggregations. We believe this neoplasm originated from pluripotent stem cells destined to become sebaceous stem cells or from sebaceous stem cells, which also have the ability to differentiate within apocrine glands.     

Composite Tumor Associating Trichoblastoma and Seborrheic Keratosis

Seborrheic keratosis is a common benign epidermal tumor histologically composed of basaloid and squamous cells. It mainly occurs on the face, scalp, and trunk, and presents clinically as a well-circumscribed, brownish to black papule, nodule, or plaque. Trichoblastoma is a relatively rare benign, slow-growing tumor showing differentiation toward the primitive hair follicle. It clinically manifests as a solitary, skin to erythematous colored, well-circumscribed dermal nodule located predominantly on the head and neck with a predilection for the scalp. Histologically, a well-demarcated mass of follicular germinative cells that show various degrees of differentiation, arranged in lobules, sheets, and nests, is located in the dermis or subcutaneous fat layer. We report the case of a 28-year-old female patient with a solitary, 2.0×4.0-cm black plaque with a 0.7-cm skin-colored nodule on the scalp. Histologically, the entire black plaque had prominent hyperkeratosis, acanthosis, and papillomatosis with horn cysts. The central nodule showed well-circumscribed, various-sized dermal tumor lobules without a connection to the overlying epidermis. The lobular aggregation was composed of numerous basaloid epithelial nests and multiple primitive papillary structures with distinct peripheral palisading of nuclei. According to these findings, the scalp lesion was diagnosed as a composite tumor associating trichoblastoma and seborrheic keratosis.     

Rippled-pattern sebaceoma.

A 71-year-old woman had a dome-shaped, slightly erythematous nodule on the anterior scalp. The nodule histopathologically revealed sebaceoma based on the silhouette and cytology. A notable and unique finding was often observed in the aggregations of sebaceoma; an arrangement of small, monomorphous, cigar-shaped basaloid cells in linear rows parallel to one another, resembling the palisading of nuclei of Verocay bodies, namely a rippled-pattern. Although we are not certain that sebaceoma can be clearly separated from trichoblastoma with sebaceous differentiation in all cases, in the present case, the absence of an abundant and densely fibrotic stroma, of follicular differentiation, and of a palisading border in the neoplastic aggregations as well as the presence of many vacuolated cells and tiny duct-like spaces favors the diagnosis of sebaceoma rather than trichoblastoma with sebaceous differentiation. Based on the expression patterns of CKs as well as similar cytological features between germinative cells in our case and immature cells in the mantles of normal vellus follicles, we believe that rippled-pattern sebaceoma is composed of immature sebaceous germinative cells with some foci of advanced sebaceous differentiation (toward the sebaceous duct and sebaceous lobule).     

A Case of Superficial Epithelioma with Sebaceous Differentiation

Superficial epithelioma with sebaceous differentiation developed on the left cheek of a 58-year-old man over a three-year period. Biopsy of the lesion demonstrated plate-like lobules of basophilic basaloid cells with broad attachments to the overlying epidermis. Clusters of or solitary sebaceous cells were present within the lobules. Three tumor types were considered; a subtype of sebaceoma growing in the epidermis, an acanthotic seborrheic keratosis subtype with sebaceous differentiation, or a tumor of the follicular infundibulum with sebaceous differentiation.     

Basaloid large cell lung carcinoma presenting as cutaneous metastasis at the colostomy site after abdominoperineal resection for rectal carcinoma

The occurrence of a tumor at the colostomy site after abdominoperineal resection for rectal carcinoma is rare and it may be related to a previously resected carcinoma or another primary tumor. We report a 61‐year‐old man who developed an ulcerated skin nodule at her colostomy site 6 years after resection of a rectal adenocarcinoma. Histopathologically, the skin nodule was composed of atypical large and pleomorphic cells with high mitotic rate and they were arranged in nests and within lymphatic channels in the dermis. The neoplastic cells were immunoreactive for cytokeratin (CK) AE1/3, CK7, CK34ßE12, epithelial membrane antigen and vimentin while detection of human papillomavirus and Epstein–Barr virus DNA was negative. A diagnosis of basaloid large cell carcinoma of pulmonary origin was suggested and it was confirmed by computed tomography‐guided fine needle aspiration of a right subpleural mass. A metastatic tumor at the colostomy site is an exceptional finding and may be the first manifestation of lung cancer, especially if it consist of pleomorphic large cells with high mitotic rate and basaloid immunophenotype.     

Cutaneous Mixed Tumor Containing Ossification,Hair Matrix,and Sebaceous Ductal Differentiation

A 58-year-old Japanese male presented with a cutaneous mixed tumor containing ossification and hair matrix differentiation on the left side of the chin. Histologically, the tumor consisted almost exclusively of apocrine-type epithelial ductal structures and chondroid stroma. Strands and aggregation of basaloid cells which contained keratinous cystic structures with a column of shadow cells arising from basophilic basaloid cells, sebaceous duct-like structures, and ossification in the stroma were also evident. These findings suggest that cutaneous mixed tumors with ossification and hair matrix differentiation are related to both the whole hair follicle and the sweat aparatus.     

Basaloid folliculolymphoid hyperplasia with alopecia as an expression of mycosis fungoides (CTCL)

Follicular mucinosis, papules, cysts and comedones have been previously described as expressions of follicular involvement by mycosis fungoides. We report a patient with mycosis fungoides who developed extensive alopecia. Multiple scalp biopsies showed perifollicular and intrafollicular infiltrate of lymphocytes but no evident follicular mucinosis. On transverse sections many of the follicles showed an absence of differentiation towards hair sheath, canal, sebaceous gland or hair formation, but instead formed undifferentiated basaloid structures. These basaloid structures showed transition from atrophic telogen follicles to hypertrophic basaloid islands infiltrated by lymphocytes, resembling the pattern previously described in cutaneous lymphadenoma. Immunophenotyping showed a predominance of helper T-cells which, on ultrastructural examination, showed cerebriform nuclei. The unusual histological findings in our case may be analogous to the hyperplasia seen in sweat glands in syringotropic mycosis fungoides (syringolymphoid hyperplasia), and we propose the term basaloid folliculolymphoid hyperplasia to describe this feature. Basaloid follicular hyperplasia has been previously described as a component of follicular mucinosis but may apparently develop in the absence of overt mucinosis.     

Rippled-pattern sebaceoma: a report of a lesion on the back with a review of the literature

A 68-year-old Japanese man presented with a nodule that had been present for 5 to 6 years on the right side of the back. Physical examination revealed a dome-shaped, 12 x 13-mm, dark red nodule. It was excised with a 2 to 3-mm margin. The patient remained free of disease during 77 months of follow-up. Microscopic examination revealed a bulb-like tumor in the dermis, contiguous with the overlying epidermis. It was composed of small, monomorphous, cigar-shaped basaloid cells in linear, parallel rows, resembling the palisading of nuclei of Verocay bodies, and presenting a rippled-pattern. There were scattered cells showing sebaceous differentiation with vacuolated cytoplasm and scalloped nuclei. There were tiny, duct-like spaces. The tumor revealed characteristics of rippled-pattern sebaceoma. The present case is the first reported rippled-pattern sebaceous neoplasm on the back. Many spindle cell tumors, such as basal cell carcinoma, pleomorphic adenoma, dermatofibrosarcoma protuberans, myofibroblastoma, and leiomyoblastoma, in addition to trichoblastoma and sebaceoma, can have a rippled-pattern.