A Rare Cutaneous Adnexal Tumor: Malignant Proliferating Trichilemmal Tumor

Epidemiology, clinical characteristics, treatment, and outcomes of proliferating pilar tumors: A systematic review

BACKGROUND

Proliferating pilar tumors (PPTs) are rare cutaneous neoplasms arising from hair follicles that have both malignant and metastatic potential.

OBJECTIVE

To present a systematic review of the epidemiology, clinical characteristics, and treatment and outcome data on PPTs.

METHODS

Using the OVID platform, MEDLINE and Embase were searched from inception until May 26, 2022. All studies that provided original data on PPTs in English were included. References of these studies were also cross-checked to identify any additional relevant articles. Oxford's Levels of Evidence-Based Medicine was used for quality assessment.

RESULTS

A total of 114 articles, providing data on 361 cases of PPTs, were included in our synthesis. Every study included was either a case series or case report. The mean age at diagnosis was 61.7. Most patients in the synthesis were female (71%), and the majority of cases occurred on the scalp (73.1%). The presence or absence of cytological atypia was only reported in one-third of the cases; 36.8% of cases were classified as malignant and 7.5% metastasized. Although no lesions treated with Mohs micrographic surgery required adjuvant radiation and only one reported recurrence occurred after Mohs surgery, there is insufficient data to make conclusions on a superior treatment modality.

LIMITATIONS

All studies in this review were either case reports or case series.

CONCLUSIONS AND RELEVANCE

Our study supports the notion that PPTs occur most commonly on the scalp of elderly female patients. Moreover, our findings confirm that PPT is capable of demonstrating aggressive biology and metastasis. Given the lack of uniformity in histologic description, pathologists should be encouraged to comment on the presence and degree of cytological atypia when reporting cases of rare neoplasms such as the PPT. Greater consensus on diagnosis and classification as well as more robust data is needed regarding optimal management.

Local narrow margin excision sequential with modified ALA-PDT for successful treatment of an 86-year-old patient with malignant proliferating trichilemmal tumor

Malignant proliferating trichilemmal tumor (MPTT) is thought to represent the malignant counterpart of benign proliferative pilar cyst, a lesion originating from the outer hair root sheath. We report a case of an 86-year-old woman with an exophytic nodule containing an ulcerated surface in the temporal region. Histopathologically confirmed MPTT without metastasis, and considering the risk of metastasis and recurrence, we used single local narrow margin excision combined with modified 5-aminolevulinic acid-mediated photodynamic therapy (ALA-PDT). No recurrence of skin lesions was found in the 2-year follow-up after combined therapy. In conclusion, local narrow margin excision sequential with modified ALA-PDT may be a particularly promising and effective treatment option for MPTT.

Malignant Proliferating Trichilemmal Tumor: A Subtle Presentation in an African American Woman and Review of Immunohistochemical Markers for This Rare Condition

A malignant proliferating trichilemmal tumor (MPTT) is thought to represent the malignant counterpart of a benign proliferating trichilemmal cyst, a keratin-filled lesion that derives from the outer hair root sheath. The clinical appearance of MPTTs does not always correlate with their histopathologic behavior, emphasizing the need for biopsy and histopathological analysis. Here, we present a 46-year-old African American woman who was evaluated for an ostensibly benign cyst on her scalp that was diagnosed as an MPTT following histopathological examination. She was treated with simple surgical resection that was flush with the cyst margins, followed by Mohs surgery to ensure complete resection. As immunohistochemistry (IHC) has often been used to characterize MPTTs, we also review the various IHC markers reported in the literature.

Current Diagnosis and Treatment Options for Cutaneous Adnexal Neoplasms with Follicular Differentiation

Neoplasms derived from follicular tissue are extremely rare. Clinically, they are reported as non-symptomatic, slow-growing nodules. These lesions are mainly benign, but the malignant type can occur. Mainly middle-aged people (50-60 years of age) are affected. These carcinomas are mainly localized on the head and neck or torso. They can be locally aggressive and infiltrate surrounding tissue and metastasize to regional lymph nodes. In the minority of cases, distant metastases are diagnosed. Quick and relevant diagnosis is the basis of a treatment for all types of tumors. The patient's life expectancy depends on multiple prognostic factors, including the primary tumor size and its mitotic count. Patients should be referred to a specialized skin cancer center to receive optimal multidisciplinary treatment. This article tries to summarize all the information that is currently available about pathogenesis, diagnosis, and treatment methods of follicular tumors.

Aggressive squamous cell carcinoma of the cranium of a dog

BACKGROUND

The authors report a case of keratinized squamous cell carcinoma (SCC) in a 14-year-old dog with extensive cranial bone invasion. To our knowledge, this is the first description of such a case of cranial keratinized SCC with aggressive generalized osteolysis described in a dog.

CASE PRESENTATION

The 14-year-old dog was referred for radiological examination with suspicion of head trauma with clinical signs of head deformation, exophthalmos and nasal discharge. The skull radiographs showed a large osteolytic defect of the frontal bone and parietal bone in the region of the external sagittal crest. Findings from the skull CT scan included generalized osteolysis in the region of parietal bone, frontal bones, maxilla on the right side and the nasal bone including the dorsal nasal concha. In the area of bone loss, new soft tissue formation with multifocal foci of mineralization was visible. The ultrasound examination revealed hypoechogenic changes with hyperechoic foci consistent with mineralization and poor vascularization. The brain and ocular structures were without visible changes. Fine needle aspiration cytology (FNAC) was performed, and squamous cell carcinoma was suspected. After 3 months, the re-presented to the clinic. The dog became progressively listless, his appetite was decreased, and he became acutely blind. Follow-up skull CT scan revealed significant osteolysis, which affected a significant aspect of the cranium. All bone defects had been replaced by new 3.5 cm-thick soft tissue formations with multifocal small 1-2 mm areas of mineralization. There was no evidence of metastasis. Histological examination confirmed the suspicion of squamous cell carcinoma.

CONCLUSIONS

This paper is the first report of cranial SCC in a dog causing extensive bone osteolysis. The lesions in this dog originated from the frontal and parietal bones including frontal sinuses. There are variants of tumors that arise from squamous epithelium or resemble SCC in the skull. These examples include adenosquamous carcinoma and proliferating trichilemmal tumours. In addition, there is possible malignant transformation caused by papilloma viruses. In the veterinary literature, there is only one similar description of adenosquamous carcinoma in a cat with similar clinical manifestations. It is justified to suspect a process of neoplastic epithelial origin in all cases of aggressive and extensive skull bone lysis. This issue should be subject to further investigation.

Trichilemmal carcinoma in an unexposed area of the nose: A case report

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Trichilemmal carcinoma (TC) is a rare malignancy originating in hair follicles.

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TC usually occurs in photo-exposed areas.

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We report a rare case of TC in a non-sun-exposed area of the nose.

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Surgical excision with wide margins prevents local recurrence.

Introduction

Trichilemmal carcinoma (TC) is a rare, low-grade, cutaneous malignant lesion that originates from hair follicle cells. It usually occurs in photo-exposed areas, especially on the face, scalp, neck, and dorsal part of the hand. We report a case of an adult female with TC in an unexposed area of the nose, which completely obstructed the right nasal cavity.

Case presentation

An 82-year-old female presented with TC in a non-sun-exposed area of the nasal cavity, which grew progressively over one year and caused nasal obstruction. The mass had dimensions of 15cm × 8cm, and it was removed surgically with a wide and deep excision. Histopathological examination confirmed the diagnosis of TC. A follow-up at three years post-surgery revealed no signs of recurrence.

Conclusion

Surgical excision with wide margins improved the treatment outcome by preventing local recurrence and providing satisfying cosmetic results.

Proliferating Pilar Tumors: Can Immunohistochemistry Differentiate Benign and Malignant Forms?

BACKGROUND

Proliferating pilar tumor (PPT) is an adnexal tumor of purported differentiation toward the follicular outer root sheath. Immunohistochemistry has been suggested to differentiate between benign and malignant forms.

METHODS

Eleven benign (PPT) and 9 malignant PPT lesions were reviewed; Ki67, p27, and p53 were applied. The staining intensity (strong, moderate, weak, and negative), positive cell numbers, and marker indexes (%) were scored using image-analysis software (ViraSoft).

RESULTS

Overall, there was no significant correlation between Ki67 and p53 and histopathological features. However, malignant PPTs had significantly lower numbers of p27-positive cells (P = 0.030).

CONCLUSIONS

Our study includes the largest group of patients in whom image analysis of p53, Ki67, and p27 has been used to try to separate benign from malignant lesions. Although there were no significant differences regarding Ki67 and p53, malignant lesions have a statistically lower expression of p27. Further studies may be needed to determine the clinical usefulness of image analysis in this differential diagnosis.

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.

Malignant proliferating trichilemmal tumour

Proliferating trichilemmal tumours are benign but locally aggressive skin neoplasms arising from hair follicles. Rarely, they can become malignant and must be appropriately managed to prevent recurrence and metastasis. One must have a low threshold for diagnosing this rare neoplasm.

Atypical Proliferating Trichilemmal Cyst with Malignant Breast Skin Transformation: A Case Report and Review of the Literature

Proliferating trichilemmal tumors (PTTs) are benign adnexal skin neoplasms that arise from the outer root sheath of the hair follicle. These tumors are most commonly observed on the scalp and occur, most of the time, in elderly women. Malignant transformation of these neoplasms is a rare event; less than 50 cases have been reported in the English medical literature. We present the case of a 39-year-old Hispanic woman with a tumor located on the skin of one of her breasts that in her third surgical procedure the histologic examination revealed the presence of a malignant proliferating trichilemmal tumor (MPTT). Furthermore, a review of the medical literature and a discussion of the clinical and pathologic features of this rare entity are provided.