Tricholemmal carcinoma. A clinicopathologic study of 13 cases

Follicular (Infundibular-Tricholemmal) Squamous Cell Carcinoma: A New WHO Entity. Clinicopathological Features in 103 Cases, Including Follow-Up and Implications for Patient Management

AIMS

Cutaneous follicular (infundibular-tricholemmal) squamous cell carcinoma (FSCC) is a new World Health Organization entity. We present the largest series of published cases, summarizing clinical data, diagnostic criteria, differential diagnosis, and implications for patient management.

METHODS

Cases were identified from 2004 to 2011. Inclusion criteria included discrete attachment(s) of the tumor to the overlying epidermis via follicular infundibula, tricholemmal keratinization, and cellular pleomorphism. Keratoacanthoma and lesions with adjacent bowenoid epidermal dysplasia were excluded.

RESULTS

One hundred three cases of FSCC identified. 48.5% demonstrated completely circumscript borders ( in situ for practical purposes), 12.6% uncertain for invasion (overwhelmingly pushing borders), and only 38.8% as clearly invasive. Follicular mucin in acantholytic spaces within tumor epithelium was a distinctive finding in 57.2% of cases. Clinical data indicated predominance in elderly (median 78.5 years) men (70.4%), with preferential head and neck location (81.6%). Many were clinically suspected as squamous cell carcinoma (48.5%). However, a significant minority were clinically diagnosed as basal cell carcinoma (40.8%). This may reflect that FSCC commonly presented as a papule or nodule (51.3%). By contrast, keratoacanthoma was less frequently suggested (17.2%) and still fewer lesions were suspected to be actinic keratosis/Bowen's disease (13.6%). Follow-up in 82 cases (median 26.5 months, range 3-144) identified 5 (6.1%) local recurrences. There was no instance of metastasis in the subgroup of lesions with completely circumscript borders. Three of 45 (6.7%) patients, with follow-up, considered to have tumors with invasive pushing, and/or infiltrative borders developed lymph node metastases.

CONCLUSIONS

FSCC is identified as a common skin cancer, incorporating historical entities, such as infundibular carcinoma and tricholemmal carcinoma, with readily identifiable histologic features. Correct diagnosis has implications for patient management; a significant subgroup of lesions show completely circumscript borders that are considered in situ for practical purposes.

Systematic analysis and case series of the diagnosis and management of trichilemmal carcinoma

Background

Trichilemmal carcinoma (TLC) is a rare malignant cutaneous adnexal neoplasm, with no relatively comprehensive research.

Objective

The aim of this study is to perform an updated statistical analysis so as to better understand TLC's epidemiology, clinical features, diagnosis, and treatment.

Methods

The diagnosis and treatment of three TLC cases in our department were summarized. Then, all TLC cases published in the literature were retrieved for a comprehensive analysis, followed by the analysis of global trends and regional distribution, demographic characteristics, clinical features, pathogenesis, histopathological features, and treatment and prognosis of TLC.

Results

Of the 231 cases, the incidence of TLC has shown an upward trend recently, especially in China, in Asia. The susceptible population is men aged 60-80 and women over 80, and the most prone location is head and neck. The phenotype of TLC is not always typical and may be misdiagnosed because of the coexistence of other diseases. There is a linear relationship between the diameter and its duration or thickness. UV, locally present skin lesions, trauma, scarring, organ transplantation, and genetic disorders may trigger the occurrence of TLC. Periodic acid-Schiff staining and CD34, but not Epithelial Membrane Antigen (EMA), were helpful in the diagnosis of TLC. Although effective, surgical excision and Mohs micrographic surgery need further improvement to reduce recurrence of TLC. Carcinoma history is an independent risk factor for TLC recurrence.

Limitations

The limitation of this study is the lack of randomized controlled trial on TLC treatment and recurrence.

Conclusion

TLC has the possibility of invasive growth and recurrence, especially in patients with longer duration and carcinoma history.

A Rare Case Report of Trichilemmal Carcinoma

Trichilemmal carcinoma (TC) is a rare skin malignant tumor with pillar differentiation. TC presents along with other malignant hair follicle tumors and accounts for only 1% of all adnexal carcinomas. TC usually occurs on sun-exposed skin in elderly people, nevertheless, it can occur at any age. We report a case of trichilemmal cyst carcinoma in a 54-year-old woman presenting with an increasing occipital cyst. A histological examination confirmed the diagnosis and a large excision was performed. Despite the absence of a well-defined consensus on the management of TC, surgical excision with adequate margins seems to be safe in the absence of metastatic lesions. However, in the case of second localization, chemotherapy could be initiated, but again, in this case, no consensus on the appropriate protocols exists.

Trichilemmal Carcinoma of the Scalp in a Young Female: A Case Report

Trichilemmal carcinoma (TC) is a rare malignant cutaneous adnexal neoplasm originating from the outer root sheath of hair follicles, which occurs commonly in sun-exposed areas of the elderly. Here, we introduce a case of a 24-year-old woman with TC on her scalp.

Clear Cell Proliferations of the Skin: A Histopathologic Review

ABSTRACT

Cutaneous clear cell proliferations encompass a heterogenous group of several primary cutaneous neoplasms and metastatic tumors with different histogenesis. Many of these clear cell proliferations may seem strikingly similar under the microscope resulting in challenging diagnosis. In many of these clear cell lesions, the reason for the clear or pale appearance of proliferating cells is unknown, whereas in other ones, this clear cell appearance is due to intracytoplasmic accumulation of glycogen, mucin, or lipid. Artifacts of tissue processing and degenerative phenomenon may also be responsible for the clear cell appearance of proliferating cells. Awareness of the histopathologic findings as well as histochemical and immunohistochemical techniques are crucial to the accurate diagnosis. This review details the histopathologic features of clear cell cutaneous proliferations, classifying them according their type of differentiation and paying special attention to the histopathologic differential diagnosis among them.

Cutaneous tricholemmal carcinoma: a 15-year single center experience

BACKGROUND

Clear cell morphology has been described in several cutaneous neoplasms either as a specific feature of some entities either as a morphological variant in the spectrum, and these two entities are frequently considered together in the differential diagnosis.

METHODS

We reviewed our series of cases occurred in our laboratory in order to further quantify the number of cases showing morphological features of tricholemmal differentiation and to investigate other clinical or histological difference. We retrieved 91 cases and, for each of them, all the clinical data regarding age, sex, clinical features, and clinical suspicious were collected, when available.

RESULTS

The revision of the specimens concluded with a final diagnosis of tricholemmal carcinoma in 15 cases (17%), all the other cases were thus considered as squamous cell carcinoma with clear cell features. No statistically significant correlations were observed with the demografic or clinicopatholagical parameters such as age, sex or dimensions, but morphological revision highlighted a potentially greater "vertical" growth frequently not matched by a concomitant radial one in tricholemmal carcinoma than in squamous tumors.

CONCLUSIONS

The debate upon the diagnostic distinction of these tumors is still ongoing with authors proposing the tricholemmal carcinoma as a variant of a squamous cell carcinoma rather than a distinct entity. Further studies are needed to confirm our data and to evaluate the reproducibility of this feature.

Could EMA and cytokeratin 7 be useful in distinguishing tricholemmal carcinoma from clear-cell squamous cell carcinoma? A case series from our department and a brief review of the literature

Tricholemmal carcinoma is a malignant cutaneous adnexal tumor showing outer root sheath differentiation, thought to be the malignant counterpart of trichilemmoma. Although the real existence of tricholemmal carcinoma continues to be a matter of debate, it has been introduced in the recently published 4th edition of World Health Organization classification of skin tumors. Herein, we evaluated whether immunohistochemistry (EMA, CK7, CK5/14, p63, p16, and Ber-EP4) supports tricholemmal carcinoma as a separate entity and whether it could be useful in this differential diagnosis. A total of 9 cases, 3 tricholemmal carcinomas and 6 clear-cell squamous cell carcinomas were evaluated on the basis of histological criteria suggested by the WHO. In our opinion, although these results need to be validated in larger series, they support tricholemmal carcinoma as a separate entity and suggest an immunohistochemical profile (clear-cell squamous cell carcinomas: EMA diffusely positive, CK7 negative; tricholemmal carcinoma: EMA negative, CK7 patchy or moderately positive) that could be useful for this differential diagnosis.

Surgical Treatment of Trichilemmal Carcinoma

Background

To investigate the clinicopathologic characteristics and prognostic factors of trichilemmal carcinoma (TC), and to determine an optimal treatment strategy for these patients.

Methods

This retrospective study enrolled consecutive patients who were admitted to the Sun Yat-sen University Cancer Center between 1998 and 2012.

Results

The key prognostic factors influencing the survival were lymph nodes metastasis and surgery margin. Multivariate analysis revealed that there was no risk factor for patient survival.

Conclusions

Surgery margin and lymph nodes metastasis were prognostic factors that influenced the treatment outcome. Simple excision with 1 cm margins is safe, inexpensive and effective for the treatment of TC; and postoperative follow-up of the patient to facilitate early diagnosis of the recurrence and distant metastasis is necessary. Systemic chemotherapy should be considered for the distance metastases patients.

CD34 and BerEP4 Are Helpful to Distinguish Basaloid Tricholemmoma From Basal Cell Carcinoma

Tricholemmoma, a benign follicular neoplasm with outer root sheath differentiation, typically comprises clear or pale cells, and when multiple is pathognomic of Cowden's syndrome. The tumor is probably underrecognized and in basaloid examples can be difficult to distinguish from basal cell carcinoma (BCC). We studied 55 tricholemmomas (including 15 basaloid cases) and compared immunohistochemical profile with nodular BCC from our archives. Basaloid and non-basaloid tricholemmomas had similar staining characteristics. BerEP4 was focally positive (range 10%-20%) in only 3/39 (7.7%) tricholemmomas compared with widespread positivity in BCC (90.8%, 139 of 151 cases with ≥50% tumor area stained). CD34 was expressed, usually focally (median 20%, range 10%-90%), in 52/53 (98.1%) tricholemmomas and was negative in all 21 BCCs stained. EMA staining lacked sensitivity or specificity in differentiating tricholemmoma from BCC. Five or more Merkel cells were found in 7/17 (40.1%) tricholemmomas and 1/23 (4.3%) nodular BCCs studied. In summary, immunohistochemistry is helpful in distinction between tricholemmoma, including difficult basaloid examples (BerEP4 negative or focal, CD34 positive) compared with BCC (BerEP4 widespread in most cases, CD34 negative). The presence of 5 or more Merkel cells is a relatively specific but not a particularly sensitive discriminator.

Malignant tumor of outer root sheath epithelium, trichilemmal carcinoma. Clinical presentations, treatments and outcomes

OBJECTIVES

To emphasize different clinical features of tumor that can be misdiagnosed clinically.

METHODS

A total of 8 cases operated between September 2009 and 2016 at the Celal Bayar University, Faculty of Medicine were included in the study. Patients' clinicopathological features, type of surgery and follow up information were evaluated. Results: Six patients were male. The average age was 75.50. The lesions were located on the head and neck, and chest wall. Six patients had a history of the rapid growth of lesion. There was no metastasis at the time of diagnosis. None of the patients needed adjuvant therapy. Mean follow up time was 19.37 months. None of the patients developed recurrence or metastasis. Conclusion: This tumor resembles basal or squamous cell carcinoma. The histopathological evaluation may lead to misdiagnosis. Regional or distant metastasis is very rare. There is no consensus about adjuvant therapy. Screening for metastasis and close follow up are mandatory.

Adnexal Carcinomas Treated With Mohs Micrographic Surgery: A Comprehensive Review

BACKGROUND

Adnexal carcinomas (ACs) are rare cutaneous malignancies of sweat gland or pilosebaceous origin. Optimal treatment and metastatic potential of AC are poorly defined. Mohs micrographic surgery (MMS) has been increasingly used to treat AC.

OBJECTIVE

To review selected primary cutaneous AC and their treatment outcomes with MMS.

MATERIALS AND METHODS

Literature review using PubMed search for articles related to primary cutaneous ACs.

RESULTS

Sebaceous carcinoma treated with MMS recurred and metastasized in 6.4% and 3.7%, respectively. Primary cutaneous mucinous carcinoma treated with MMS recurred and metastasized in 9.6% and 6.4%, respectively. After MMS, 4.7% of microcystic AC recurred with no reported metastases. After MMS, recurrences and metastases of trichilemmal carcinoma or hidradenocarcinoma have not been reported. Two (4.2%) regional lymph node metastases but no distant metastases or local recurrences have been reported in eccrine porocarcinoma. Squamoid eccrine duct tumor, pilomatrix carcinoma, and spiradenocarcinoma treated with MMS are also reviewed.

CONCLUSION

The rarity of ACs and the lack of comparative data on treatment makes conclusive recommendations on treatment difficult. Recent large case series and reviews suggest MMS is a useful and possibly superior treatment for AC and should be considered if primary cutaneous disease is suspected.

Malignant hair follicle tumors of the periorbital region: A review of literature and suggestion of a management guideline

Malignant hair follicle tumors are rare skin adnexal malignancies that have a predilection for the head and neck region. They can be categorized into a number of different subtypes. Histologically, they are distinct from their benign counterpart. To the best of our knowledge, there is no extensive review of these malignancies, especially in the periorbital region. We aim to provide a literature review and a guideline for management of these malignant tumors in the periorbital region. Database from Medline, PubMed, Embase, and Google Scholar were consulted. A total of 16 cases from the literature on hair follicle malignancies in the periorbital region were included in this review. The clinical presentations, diagnostic patterns, investigations used, and best management approach of these tumors are discussed. The American Joint Committee on Cancer (AJCC) 7(th) edition carcinoma of the eyelid staging system was used to describe their behaviors. We recommend wide excision surgery and a close follow-up for these tumors. Tumors presenting with a late stage require work-up for distant metastasis and consideration for exenteration procedures. The role of radiotherapy and chemotherapy in this context is still uncertain.

Anaesthesia for a "Scalped" Patient

Trichilemmal carcinoma of scalp is a rare malignant tumour of scalp. A 52-year-old female presented with an extensive ulcerative lesion of the scalp. As the location of the tumour was in the occipital region and there was loss of bony skull in the region, this case became challenging. This patient was managed in the left lateral which was a difficult situation for even the experienced Anaesthesiologist. Intravenous access was acquired, central venous catheter (CVC) was placed in the right internal jugular vein under ultrasonography (USG) guidance and intubation was carried out in the lateral position. After the procedure, patient was again returned to the left lateral position. The trachea was extubated in the lateral position once the patient was awake, after thorough reversal of neuromuscular blockade. Patient had an uneventful postoperative period. This case report highlights the management of an unusual case of Trichilemmal carcinoma of the scalp.

Molecular pathology of skin neoplasms of the head and neck

CONTEXT

Skin neoplasms include the most common malignancies affecting humans. Many show an ultraviolet (UV)-induced pathogenesis and often affect the head and neck region.

OBJECTIVE

To review literature on cutaneous neoplasms that show a predilection for the head and neck region and that are associated with molecular alterations.

DATA SOURCES

Literature review.

CONCLUSIONS

Common nonmelanoma skin cancers, such as basal and squamous cell carcinomas, show a UV-induced pathogenesis. Basal cell carcinomas are characterized by molecular alterations of the Hedgehog pathway, affecting patched and smoothened genes. While squamous cell carcinomas show UV-induced mutations in several genes, driver mutations are only beginning to be identified. In addition, certain adnexal neoplasms also predominantly affect the head and neck region and show interesting, recently discovered molecular abnormalities, or are associated with hereditary conditions whose molecular genetic pathogenesis is well understood. Furthermore, recent advances have led to an increased understanding of the molecular pathogenesis of melanoma. Certain melanoma subtypes, such as lentigo maligna melanoma and desmoplastic melanoma, which are more often seen on the chronically sun-damaged skin of the head and neck, show differences in their molecular signature when compared to the other more common subtypes, such as superficial spreading melanoma, which are more prone to occur at sites with acute intermittent sun damage. In summary, molecular alterations in cutaneous neoplasms of the head and neck are often related to UV exposure. Their molecular footprint often reflects the histologic tumor type, and familiarity with these changes will be increasingly necessary for diagnostic and therapeutic considerations.

Tricholemmal carcinoma of the head and neck region: A report of 15 cases

Tricholemmal carcinoma is an extremely rare malignancy of the skin, and its biological behavior and management is controversial. The objective of the present study was to investigate the clinicopathological characteristics and management of tricholemmal carcinoma of the head and neck region. The study analyzed 15 patients with tricholemmal carcinoma. Demographic and clinical data were collected, and features associated with the management and prognosis of tricholemmal carcinoma were analyzed. Two of the 15 patients were lost to follow-up. The results showed that, during the follow-up period, 5 of the 13 available patients succumbed to the causes of recurrence (n=3), neck lymph node metastasis (n=1) and Parkinson's disease (n=1). No patients developed distant metastasis. The disease-free survival (DFS) and overall survival (OS) were 31.1±7.8 and 32.9±7.4 months (mean ± SE), respectively, and the DFS and OS rates were 69.2 and 61.5%, respectively. In conclusion, the biological behavior of tricholemmal carcinoma is locoregionally aggressive. The recommended management for head and neck tricholemmal carcinoma is radical resection and neck dissection, and post-operative radiotherapy may be considered for high-risk patients.

Cystic tricholemmal carcinoma in situ

An 89-year-old man presented with a clinically cystic 4-mm papule on the left temple. The clinical impression was a benign cyst. Pathologic examination revealed a small, symmetric-appearing, well-circumscribed, dermal-based cystic lesion with markedly atypical-appearing clear to squamoid cells lining the cyst wall, consistent with carcinoma in situ involving the cyst. The cells showed abundant glycogen-containing cytoplasm (confirmed by Periodic acid Schiff stains with and without diastase), consistent with tricholemmal differentiation, and areas of tricholemmal/pilar-type keratinization (without a granular layer), consistent with tricholemmal carcinoma in situ, most likely arising in a tricholemmal/pilar cyst. Ki-67 and p53 immunohistochemical stains were strongly positive (with more than 20% of nuclei staining on Ki-67 and more than 80% on p53) in the cyst-lining cells, further supporting the interpretation of carcinoma in situ. Multiple deeper level sections were examined but did not show any evidence of an associated invasive carcinoma. Tricholemmal (pilar) cysts are common benign adnexal lesions and atypia/dysplasia or carcinoma in situ arising within them is exceedingly rare. Previously, only one case of a tricholemmal cyst with carcinoma in situ has been reported. That case was associated with an atypical fibroxanthoma. We report only the second case of tricholemmal carcinoma in situ, most likely involving a tricholemmal cyst, which was not associated with another tumor or evidence of invasive carcinoma.

Trichilemmal carcinoma: an unusual presentation of a rare cutaneous lesion

Trichilemmal carcinoma (TC) is a rare cutaneous neoplasm which is derived from adnexal keratinocytes, is histologically invasive, contains cytologically atypical clear cell neoplasm and is in continuity with the epidermis and/or follicular epithelium. However, the diagnostic criteria and even the existence of TC have been contentious. We report the case of a 92-year-old woman with TC of the head and neck region who presented with an unusually long history. She was treated successfully with wide local excision. Important aspects in presentation, differential diagnosis, including histopathological features and management are discussed.

Survival study and clinicopathological evaluation of trichilemmal carcinoma

Trichilemmal carcinoma (TC) is a rare malignancy, commonly located on the scalp, forehead and neck, trunk or the upper extremities. The aim of this study was to investigate the clinicopathological characteristics and prognostic factors of TC, and to determine an optimal treatment strategy for these patients. Consecutive patients who were admitted to the Sun Yat-sen University Cancer Center between 1998 and 2012 were included in this retrospective study. The key prognostic factors affecting survival were lymph node metastasis and surgery margin. Multivariate analysis demonstrated that there was no risk factor for patient survival. Surgery margin and lymph node metastasis were the prognostic factors that influenced the treatment outcome. Simple excision with 1 cm margins is safe, cost-effective and effective for the treatment of TC. Additionally, postoperative follow-up of the patient in order to facilitate early diagnosis of recurrence and distant metastasis is necessary. Systemic chemotherapy should be considered in the case of patients with distant metastases.

Recurrent proliferating trichilemmal tumor of the vulva: a case report

Proliferating trichilemmal tumor (PTT) is a rare but morphologically distinct tumor that usually arises on the scalp of elderly women. It is composed of multiple cysts consisting of squamous epithelium with trichilemmal keratinization without granular layer interposition. Vulvar proliferating trichilemmal cyst is very rare, with, to the best of our knowledge, only 3 cases previously reported in the literature. We describe a 39-year-old woman with recurrent PTT on the left labium majus of the vulva, which had been excised from the same side 5 years before. She had a palpable nodule, approximately 2 cm in size, which was firm, mobile, and nontender; without erythema and ulceration; and covered by normal skin on the vulva. There was no inguinal lymphadenopathy. The lesion was removed by wide surgical excision; because of the tissue elasticity, primary closure was possible. The pathology result was reported as proliferating trichilemmal carcinoma with tumor-free margins. Although local recurrence after wide excision is rare, we recommend complete excision for treatment of PTT and long-term follow-up because of the possibility of recurrence.

Trichilemmal carcinoma: case report

The trichilemmal carcinoma is a rare tumor that usually occurs on sun-exposed skin, especially on the face, scalp, neck and back of hands, mainly in elderly subjects but commonly between the 4th and 9th decades of life. It is not a gender-based illness. This study shows a difficult to treat case of recurrent trichilemmal carcinoma on the same location of a basal-cell carcinoma previously treated with surgery and radiotherapy.

Tricholemmoma and clear cell squamous cell carcinoma (associated with Bowen's disease): immunohistochemical profile in comparison to normal hair follicles

There have been only a few reported comparative immunohistochemical studies of normal hair follicles and tricholemmomas. Clear cell squamous cell carcinomas (SCCs), which are derived from Bowen's disease, histopathologically mimic or are difficult to distinguish from tricholemmal carcinoma. The purpose of and methods used in the present study are as follows: (1) evaluation of whether the immunohistochemical profile (cytokeratin (CK)1, CK10, CK17, CD34, and D2-40) in normal hair follicles is retained in tricholemmomas (11 lesions); and (2) a study of the immunohistochemical profile of in situ or superficially invasive clear cell SCCs (associated with Bowen's disease) (10 lesions) to investigate the presence or absence of tricholemmal differentiation markers in these lesions. The present study demonstrated that (1) the immunohistochemical profile of the normal outer root sheath cells was generally retained in tricholemmomas; (2) in contrast to the D2-40 expression in tricholemmomas (only a peripheral pattern, which is similar to that in the normal outer root sheath), the CD34 expression in tricholemmomas represented in a diffuse pattern, a peripheral pattern, and a combined diffuse and peripheral pattern; (3) tricholemmomas are benign neoplasms with outer root sheath (below the isthmus) differentiation, which characteristically show upregulation of CD34 expression with some functionally similar conditions to the terminal hair follicles in the anagen phase; and (4) there is no clear immunohistochemical evidence of tricholemmal differentiation in clear cell SCC (associated with Bowen's disease).

Recurrent trichilemmal carcinoma with a large cutaneous horn formation

We describe an unusual case of trichilemmal carcinoma accompanied by a large horn formation in a 79-year-old man who presented with a brown tumor mass including a 15-cm-long horn on the vertex for one and a half years. Two months after the surgical removal of the primary tumor, the tumor recurred with a dimension 10x8x8 cm. The tumor was then excised again and the wound was covered using skin from the patient's back. Microscopically, the tumor showed histology consistent with trichilem¬mal carcinoma. After 2 years, the patient had not shown any recurrence or metastases. We highlight the features that distinguish trichilemmal carcinoma from the other malignant tumors, such as squamous cell carcinoma, basal cell carcinoma, nodular melanoma, or keratoacanthoma.

Desmoplastic trichilemmoma of the facial region mimicking invasive carcinoma

Trichilemmoma is a hamartomatous proliferation arising from cells of hair follicle. Its desmoplastic variant simulates an invasive carcinoma. In this tumor, the cell of origin seems to be located in the superficial level of the hair follicle just below the basement membrane at the sebaceous gland level. We present a similar case which presented with an asymptomatic nodular lesion in the region above the upper lip on left side. Fine needle aspiration cytology raised the cytological possibility of a malignancy for which the lesion was excised. On histopathology the lesion was diagnosed as desmoplastic trichilemmoma. The case highlights the difficulty encountered in differentiating a benign adnexal tumor from malignant lesion based on cytology alone. Moreover, the extensive desmoplasia on histopathology raises the suspicion of invasive malignancy which requires to be carefully excluded. The superficial features of trichilemmoma and lack of cellular atypia is a useful diagnostic clue in such a situation. Positivity of CD34 can also be used to differentiate from basal cell carcinomas. The case reported here had a solitary lesion, but follow up is required for development of more lesions or multiple hamartomas in other organs as a part of Cowden's disease.

Recurrent and metastatic trichilemmal carcinoma of the skin over the thigh: a case report

Trichilemmal carcinoma (TC) is an uncommon cutaneous neoplasm that develops from the external root sheath of the hair follicle. It is considered to be a low-grade carcinoma with low metastatic potential. Local recurrence and metastasis are rare after surgical excision. We report here on a case of metastatic TC in the skin over the thigh, and this tumor was treated with cisplatin and cyclophosphamide combination chemotherapy.

Squamous cell carcinoma with clear cells: how often is there evidence of tricholemmal differentiation?

Clear-cell carcinoma of the skin was described by Kuo in 1980 as a cutaneous tumor composed of clear cells that lacked cytoplasmic glycogen or evidence of tricholemmal keratinization. Tricholemmal carcinoma (TC) is conventionally considered to be a neoplasm derived from adnexal keratinocytes with glycogenated clear cells and evidence of outer root sheath or tricholemmal differentiation. The existence of TC has been questioned as it has been argued that without clear immunohistochemical evidence of outer root sheath differentiation, TC cannot be distinguished from clear-cell carcinoma of the skin. Our laboratory has not routinely stained the cases that appear to be carcinomas with clear keratinocytes to determine if glycogen is present and has not made the diagnosis of TC. We sought to test whether the presence of glycogen, light microscopic features said to be typical of TC, or immunohistochemical findings would delineate a group of "true" TC among the cases that we have been recording as squamous cell carcinomas with clear cells (SCC-C). 40 cases of SCC-C were evaluated for 7 histologic and histochemical criteria (a lobular arrangement, peripheral palisading, tricholemmal keratinization, folliculocentricity, evidence of a preexisting tricholemmoma, the presence of intracytoplasmic glycogen, and a thickened basement membrane) said to characterize TC. Selected cases were then stained for immunohistochemical markers (CD34, CK17, and NGFR/p75) that have been used as evidence for tricholemmal differentiation in some studies. Of the 40 cases, 38 (95%) SCC-C showed intracytoplasmic glycogen (periodic Schiff positivity abolished by diastase) and 55% of cases showed foci of tricholemmal keratinization. Overall, the carcinomas showed a spectrum of the above aggregated criteria ranging from 0 to 5. None possessed all the criteria expected in an ideal TC. In addition, the majority of the selected SCC-C in this study were negative (85%) for antigens typically found in the outer root sheath epithelium of the hair follicle. The glycogen-free clear-cell carcinoma described by Kuo seems uncommon in our patient population. Rare cases of SCC-C met the majority of Headington's criteria for TC or showed immunohistochemical evidence of tricholemmal differentiation. Thus, we also conclude that well-differentiated TC is rare and its description in the literature may overstate the case that it is a well-characterized cutaneous neoplasm.

A Case of Trichilemmal Carcinoma Treated with Mohs Micrographic Surgery

Trichilemmal carcinoma is a cutaneous adnexal tumor originating from the outer root sheath of hair follicle, and it was first described by Headington in 1976. Clinically, it usually occurs as an asymptomatic solitary papule, nodule or mass on the face or scalp. This neoplasm is a malignant counterpart of trichilemmoma, and it has been reported in the literature as trichilemmal carcinoma, tricholemmal carcinoma, malignant trichilemmoma, and tricholemmocarcinoma. Although histologically, trichilemmal carcinoma frequently has maliganant features, it has a relatively benign clinical behavior. We think Mohs micrographic surgery is a useful treatment modality in trichilemmal carcinoma because the final skin defect is smaller than a wide excision. We report a case of primary trichilemmal carcinoma which had developed on the face, treated with Mohs micrographic surgery.

Trichilemmal carcinoma with neuroendocrine differentiation

We report a 12-mm nodular, cream-coloured skin lesion that appeared on the left nasal ala in an 81-year-old man. This trabecular infiltrative tumour showed keratin microcysts, stromal hyalization, cytoarchitectural malignancy features, colonizing melanocytes, and immunoexpression of epithelial membrane antigen, cytokeratin 15/20, chromogranin, synaptophysin and CD56. To our knowledge, this is the first documented case of a trichilemmal carcinoma with neuroendocrine differentiation and melanocyte colonization, which is suggested by the trabecular growth pattern and requires immunohistochemical confirmation. The colonization of the epithelial nests by nonatypical dendritic or spindle melanocytes is a clue to morphological recognition of pilar neoplasms, along with the presence of stromal induction (CD34-positive peritumoral spindle cells), catagen-like apoptotic bodies, calcifications, keratin microcysts and cell balls.

Adnexal clear cell carcinoma with comedonecrosis: clinicopathologic analysis of 12 cases

CONTEXT

Cutaneous clear cell tumors can pose a diagnostic challenge even to the experienced dermatopathologist; this is partly because of limitations of existing diagnostic categories.

OBJECTIVE

To describe a previously unrecognized, distinctive cutaneous adnexal carcinoma capable of an aggressive clinical course.

DESIGN

Clinicopathologic analysis of a series of 12 cases.

RESULTS

The patients were older individuals (median age, 71 years) with equal gender frequency. The lesions showed wide anatomic distribution with predilection for the head and neck area, especially the scalp. The lesions presented as rapidly growing, erythematous to flesh-colored, solitary papules/nodules that were capable of quickly reaching a size of several centimeters. Histologically, adnexal clear cell carcinoma with comedonecrosis was characterized by dermal proliferation of nests of epithelial cells showing distinctive zonal arrangement. The periphery of the tumor nests was formed by squamoid cells merging with centrally located clear cell areas containing foci of comedonecrosis. The lesions often showed multilobular or trabecular growth pattern and infiltrating border. Nuclear pleomorphism was variable; mitotic count ranged from 2 to 32/mm2 (median, 8/mm2). No ductal, cuticular, or apocrine differentiation was seen. All cases showed expression of epithelial membrane antigen and cytokeratin 17 in clear cells, with focal carcinoembryonic antigen expression in some cases. Follow-up (average, 37 months) revealed local recurrence (4 cases) and regional and distant metastases (2 cases).

CONCLUSIONS

Adnexal clear cell carcinoma with comedonecrosis appears to be a distinctive adnexal neoplasm that has to be distinguished from more indolent squamous cell and tricholemmal carcinomas.

Trichilemmal Carcinoma of the Skin Mimicking a Keloid in a Heart Transplant Recipient

Trichilemmal carcinoma is a rare cutaneous adnexal malignant tumor deriving from the outer root sheath of hair follicles. It is only rarely reported in recipients of solid (renal) organ transplants. We describe the first case of trichilemmal carcinoma presenting with a misleading clinical aspect in a heart transplant recipient. We then briefly outline the salient clinicopathologic features of this malignancy.

Cutaneous squamous cell carcinoma: a comprehensive clinicopathologic classification

Cutaneous squamous cell carcinoma (SCC) includes many subtypes with widely varying clinical behaviors, ranging from indolent to aggressive tumors with significant metastatic potential. However, the tendency for pathologists and clinicians alike is to refer to all squamoid neoplasms as generic SCC. No definitive, comprehensive clinicopathological system dividing cutaneous SCCs into categories based upon their aggressiveness has yet been promulgated. Therefore, we have proposed the following based upon the malignant potential of SCC variants, separating them into categories of low (< or = 2% metastatic rate), intermediate (3-10%), high (greater than 10%), and indeterminate behavior. Low-risk SCCs include SCC arising in actinic keratosis, HPV-associated SCC, tricholemmal carcinoma, and spindle cell SCC (unassociated with radiation). Intermediate-risk SCCs include adenoid (acantholytic) SCC, intraepidermal epithelioma with invasion, and lymphoepithelioma-like carcinoma of the skin. High-risk subtypes include de novo SCC, SCC arising in association with predisposing factors (radiation, burn scars, and immunosuppression), invasive Bowen's disease, adenosquamous carcinoma, and malignant proliferating pilar tumors. The indeterminate category includes signet ring cell SCC, follicular SCC, papillary SCC, SCC arising in adnexal cysts, squamoid eccrine ductal carcinoma, and clear-cell SCC. Subclassification of SCC into these risk-based categories, along with enumeration of other factors including tumor size, differentiation, depth of invasion, and perineural invasion will provide prognostically relevant information and facilitate the most optimal treatment for patients.

Cutaneous squamous cell carcinoma: a comprehensive clinicopathologic classification. Part one

Cutaneous squamous cell carcinoma (SCC) includes many subtypes with widely varying clinical behaviors, ranging from indolent to aggressive tumors with significant metastatic potential. However, the tendency for pathologists and clinicians alike is to refer to all squamoid neoplasms as generic SCC. No definitive, comprehensive clinicopathological system dividing cutaneous SCCs into categories based upon their aggressiveness has yet been promulgated. Therefore, we have proposed the following based upon the malignant potential of SCC variants, separating them into categories of low (< or = 2% metastatic rate), intermediate (3-10%), high (greater than 10%), and indeterminate behavior. Low-risk SCCs include SCC arising in actinic keratosis, HPV-associated SCC, tricholemmal carcinoma, and spindle cell SCC (unassociated with radiation). Intermediate-risk SCCs include adenoid (acantholytic) SCC, intraepidermal epithelioma with invasion, and lymphoepithelioma-like carcinoma of the skin. High-risk subtypes include de novo SCC, SCC arising in association with predisposing factors (radiation, burn scars, and immunosuppression), invasive Bowen's disease, adenosquamous carcinoma, and malignant proliferating pilar tumors. The indeterminate category includes signet ring cell SCC, follicular SCC, papillary SCC, SCC arising in adnexal cysts, squamoid eccrine ductal carcinoma, and clear-cell SCC. Subclassification of SCC into these risk-based categories, along with enumeration of other factors including tumor size, differentiation, depth of invasion, and perineural invasion will provide prognostically relevant information and facilitate the most optimal treatment for patients.

Malignant adnexal neoplasms

Malignant cutaneous adnexal neoplasms are one of the most challenging areas of dermatopathology. Tumors of the pilosebaceous apparatus can occur as single-lineage neoplasms or may manifest as complex proliferations with multilineal differentiation patterns including not only the germinative component of the hair bulb, the inner or outer root sheath epithelium and the sebaceous gland and duct, but also the sweat duct components that relate to the apocrine secretory apparatus which empties into the follicle near the follicular bulge. Eccrine and apocrine neoplasms present a bewildering array of morphologies, which often defy precise classification. The purpose of this review is to discuss in detail the malignant neoplasms of the cutaneous adnexae and their benign and prognostically indeterminate mimics.