UNASSIGNED: Pilomatrix carcinomas (PMXCs) are uncommon, locally aggressive tumors with high recurrence rates, metastatic potential, and fewer than 130 cases reported in the literature. Typically, they present as an unassuming, firm, dermal swelling and therefore are frequently mistaken for more common, benign masses, leading to undertreatment which can cause local invasion and metastatic spread. Diagnosis relies on excision with pathologic analysis; however once diagnosed, there are no current recommendations to guide treatment or surveillance for recurrence or metastases.
UNASSIGNED: Here, we present a case of one of these rare tumors. Our case describes a 1.5 × 2.5 cm firm, mobile mass at the supraorbital rim in an otherwise healthy, young patient. Prior to removal, we suspected a benign pathology; however, excision proved difficult and pathologic diagnosis was consistent with PMXC. Following discussion with tumor board, decision was made to perform Mohs micrographic surgery and staging via CT scans with regular follow-up and surveillance scans.
UNASSIGNED: PMXCs are exceedingly rare diagnoses and present like many benign lesions. Therefore, we elected to document this case to encourage providers to keep these biologically aggressive tumors on their list of differential diagnoses in an unsuspecting mass, as well as to provide our own recommendations for treatment and screening for recurrence and metastatic spread.

UNASSIGNED: A 55-year-old male patient developed a mass in the left inguinal area with left lower limb swelling and first visited a local hospital 3 months earlier because of unrelieved pain. An MRI scan suggested left suprapubic branch and left acetabular bone destruction, abnormal soft tissue signals within the iliopsoas muscle of the anterior edge of the left iliac bone, and enlarged lymph nodes in the left iliac fossa and left inguinal region. The patient subsequently underwent left pelvic lesion open biopsy and inguinal lymph node resection biopsy. According to pathological reports, the left inguinal mass was considered to be a malignant tumor of cutaneous accessory origin (pilomatrix carcinoma) with extensive vitreous changes. The suprapupubis branch mass was considered to be a bone metastatic pilomatrix carcinoma. Immunohistochemistry (IHC) revealed a PDL1 combined positive score (CPS) of 8. DNA next-generation sequencing (NGS) showed CDKN2A L65Rfs*53 mutation. The patient received three cycles of gemcitabine and nedaplatin. However, the lesion progressed.
UNASSIGNED: Chemotherapy is not effective for treating pilomatrix carcinoma. PDL1 antibodies and CDK4/6 inhibitors might be treatment options for pilomatrix carcinoma.

BACKGROUND: Pilomatrix carcinoma (PC) is a rare skin malignancy of the hair follicles matrix that tends to be locally aggressive with 10-16 % risk of metastasis mostly to the pulmonary and lymphatic system. There are no clear protocols for the management of PCs, however surgical intervention with clear margins has been highly considered in PC management to decrease risk of recurrence.
METHODS: A 40 year-old male patient presented to our clinic to evaluate an asymptomatic, slow-growing nodule localized on his left thigh. A CT scan revealed a well-defined, enhanced lesion with microcalcification. \"En bloc\" surgical resection of the lesion was performed and histopathology confirmed the diagnosis of pilomatrix carcinoma.
UNASSIGNED: Given its rarity, there are no definitive guidelines regarding PC treatment. However, surgical intervention with clear margins including wide local excision or Mohs micrographic surgery has been highly considered. In our case, wide excision of the lesion with clear margins was performed with no evidence of recurrence one year later.
CONCLUSIONS: Given the local aggressive nature of PC, appropriate surgical intervention is essential in decreasing the risk of recurrence. Wide excision with clear margins has been proposed to decrease the risk of recurrence. Additionally, total-body skin examination should be done 2-3 times annually to evaluate for recurrence or metastasis.

UNASSIGNED: A very rare skin cancer. Malignant variant of pilomatricoma. It is unique because of its highly aggressive behavior. Responds poorly to chemotherapy and radiotherapy. Treated with a wide surgical excision with safe margins.
UNASSIGNED: Pilomatrix carcinoma is uncommon and locally aggressive tumor of the hair follicle matrix. It is a malignant variant of pilomatricoma. If left untreated for a long time may attain massive size and has the potential for distant spread. Only few cases with brain extension have been reported in the literature. Diagnosis of these tumors is established by histopathology. Although pilomatrixoma and pilomatrix carcinoma are well-recognized lesions, clinically they are frequently misdiagnosed as other skin conditions. The tumors respond poorly to chemotherapy and radiotherapy. Thus, recommended treatment is a wide surgical excision with safe margins. Herein, we report the case of a 39-year-old African woman with pilomatrix carcinoma of the scalp eroding the skull bone with intracranial extension.

Pilomatrix-like high-grade endometrioid carcinoma (PiMHEC) has recently been described as an aggressive variant of endometrial carcinoma. Herein, we described a case of ovarian PiMHEC, comparing it to endometrial PiMHEC and assessing previously published cases of putative ovarian PiMHEC. A 65-year-old woman underwent hysterectomy for an ovarian tumor characterized by solid nests of basaloid cells with prominent ghost cell keratinization. Immunohistochemistry showed nuclear β-catenin and CDX2 expression and loss of estrogen and progesterone receptors and PAX8. These features were consistently observed in all previously published cases and may represent diagnostic criteria of PiMHEC. Other frequent features were geographic necrosis and a low-grade endometrioid component. CK7, neuroendocrine, and basal/squamous markers were inconsistently expressed. All cases with available follow-up showed poor prognosis. PiMHEC should be distinguished from mimickers, such as high-grade endometrioid carcinoma with geographic necrosis, low-grade endometrioid carcinoma with ghost cell keratinization, and undifferentiated/dedifferentiated carcinoma. In conclusion, PiMHEC can also occur in the ovary and shows several consistent clinical, morphological, and immunophenotypical features. These features support that PiMHEC is a distinct entity requiring an aggressive management.

Pilomatrixoma is an uncommon, benign tumor with differentiation towards both the hair matrix and cells arising in the cortex, most frequently appearing in the first or second decade of life. In rare instances, pilomatrixomas can show malignant transformation. Pilomatrix carcinoma is extremely uncommon and has traditionally been considered a tumor of low malignant potential; however, a high local recurrence rate has been reported. There is a paucity of literature on these lesions, with only a few reports describing the spectrum of malignant changes seen in these lesions. In this case report, we present a case of pilomatrixoma in an adult patient showing atypical features. While the tumor is small, there are focal features that suggest progression to malignancy, but do not fulfill the criteria for pilomatrix carcinoma. These focal atypical features include a focal infiltrative pattern at the periphery, with a variable cytological atypia and an increased mitotic rate, up to five mitotic events/high-power field. Irregular foci of central necrosis (comedonecrosis) were present in several lobules. Some of the features identified were similar to a subset of pilomatrixoma, known as \"proliferating pilomatrixoma.\" However, our case did not have the diffuse changes or larger size that has been frequently reported in \"proliferating pilomatrixoma.\" In conclusion, given the lack of focality of the changes, the lesion in our case is best described as a pilomatricoma with atypical features. Furthermore, our case may highlight the need to ensure close clinical follow-up for these lesions with unexpected atypical features that raise concern of recurrence and malignant transformation.

Pilomatrix carcinoma (PC) is a rare skin adnexal neoplasm derived from piliferous follicles, usually occurring in the head and neck region. An optimal treatment for PC has not yet been established, while surgery with wide margins is recommended, with radiation therapy (RT) and chemotherapy improving the curative effect. Location of this tumor in the breast is exceedingly rare, especially for a male. We now report an unusual case of a 53-year-old male who presented with 2 palpable masses in the right breast, which had been removed surgically about 4 and a half years prior, but recurred after 7 months. Ultrasonography revealed 2 irregular low-echo masses with a well-defined boundary, and computed tomography (CT) showed 2 soft tissue masses in subcutaneous tissue of the right breast. The tumors were completely removed without RT and chemotherapy. After about 4 years\' follow-up, the patient remains free of local recurrence and metastasis. To the best of our knowledge, only 2 cases of PC in the breast region have been reported, but were female.

Pilomatrix carcinoma is a rare malignancy stemming from aberrant proliferation of matrical cells found in developing hair. This neoplasm demonstrates a bimodal age distribution and a proclivity for developing on the head or neck. Clinically, a firm, painless, violaceous nodule with overlying ulceration is commonly described. Pilomatrix carcinoma is considered a variable-grade malignancy that tends to be locally aggressive, though metastatic disease occurs in 10 to 16 percent of cases. Mortality rates range from 7 to 9 percent. Although there is no definitive treatment protocol, surgical intervention in the form of local excision or via Mohs micrographic surgery can be considered, with radiotherapy adopted as an effective alternative for nonsurgical, recurrent, or metastatic disease. Here, we describe the case of a 62-year-old man who presented for evaluation of a red, enlarging lesion on his forehead which became tender and started to bleed shortly before the patient presented to our clinic. The patient was ultimately referred to a tertiary care center for surgical excision and, at the time of this pubilcation, has been tumor-free for more than one year. This case of a rare and often unconsidered neoplasm underscores the importance of clinical suspicion and close patient follow up to prevent local recurrence, metastasis, and death.

BACKGROUND: Pilomatrix carcinoma is a rare aggressive tumor with a high rate of local recurrence after surgical excision. Diagnosis is made by histopathology and when discovered, wide local excision has been shown to have the best results.
METHODS: We report a case of a 74-year-old male incidentally found to have a large right postauricular mass and regional lymphadenopathy. The mass was biopsied and proven to be a malignant pilomatrixoma. Wide local excision and level II and III neck dissection with reconstruction using a right supraclavicular flap was performed.
CONCLUSIONS: Pilomatrix carcinoma is a lesion first described in 1880 by Malherbe and Chenantais. It is unknown if these tumors arise de novo or arise through malignant transformation of a benign pilomatrixoma. There are similarities between the benign lesion and its malignant counterpart in terms of activating mutations in signaling pathways. A well-defined gold standard for surgical management has not been established, but currently wide local excision with safe margins is recommended along with regional lymph node dissection when metastasis is suspected. Currently, no chemotherapy regimen has been shown to be effective in local control or in preventing metastatic spread.
CONCLUSIONS: Pilomatrix carcinoma, given its aggressive nature, has a high propensity for recurrence after excision. It is important to perform wide local excision to avoid an incomplete resection and higher recurrence rates. Further studies will be needed to create a more defined standard of treatment and to evaluate the role of adjuvant chemotherapy and radiation therapy.

Pilomatrix carcinoma (PC) is a rare neoplasm, particularly in the parotid region. Thus, it is easily misdiagnosed and an optimal treatment regimen has not yet been established. The present study reports the case of a 43-year-old female who presented with a PC of the parotid region and reviews the associated published literature. The patient underwent three surgical excisions prior to the tumor being completely removed, and was misdiagnosed four times prior to the correct diagnosis. Once the tumor was completely removed, the patient received radiation therapy (RT). At the 2-year follow-up, the patient remained free of local recurrence and metastasis. To the best of our knowledge, only 3 cases of PC on the parotid region have been reported. Although an optimal treatment regimen has not been established, surgery with wide margins is recommended, with RT and chemotherapy producing mixed results.