Discussion
MAC mostly occurs in the centrofacial region, in which lips include about 50% of cases (8).
The other most common involved sites are periocular area, nose, nasolabial fold, cheek, scalp, and chin. Although MAC is mostly considered as a neoplasm of the head and neck region; the axilla, antecubital fossa, buttocks, foot, and chest are the other affected areas which have been reported in the literature (2,4,12,13).
MAC is assumed to be a non-metastatic tumor; however, Yugueros et al reported 55 patients affected to sweat gland carcinomas, in which, 17 of them declared a history of MAC which was treated by excisional surgery and radiotherapy (14). Also Lei et al. reported lymph node involvement in the contralateral region of neck in a patient with MAC, which had performed radiation and surgery as treatment 22 years earlier. They proposed that it is more possible to be the result of direct extension via perineural path rather than lymphatic spread (4,15). The supraorbital nerve can be invaded by the lesions presenting in periorbial area, particularly on the eyelid or eyebrow.
Although no defenitive cause has been found yet, some studies have reported radiation therapy, chronic sun exposure, and immuno-compromised status as predisposing factors for MAC (2,3,8,16).
History of prior radiation has been reported in 8–12% of the cases (17-19); also lesions in atypical sites, including the neck, have been seen in patients with a history of radiation on the affected area (20,21).
It is proposed that taking immuno-suppressive drugs may develop MAC lesions (22). A chronic lymphocytic leukemia (CLL) patient with scalp MAC was reported by Carroll et al. (23); as it has been reported in immuno-compromised patients several times (22-24).
In order to have a successful treatment, an accurate diagnosis is necessary. Clement et al. found that MAC can be easily misdiagnosed (25). As mentioned before, the clinical presentation of MAC could be mistaken for basal cell carcinoma (BCC), squamous cell carcinoma, cyst or scar, particularly when a biopsy is not representative of the entire lesion. Failure to obtain a proper biopsy sample could also result misdiagnosis, due to the infiltrative nature of the lesion.
We can not evaluate the treatment options of MAC properly, due to the rarity of the disease and lack of studies with long-term follow-up of the patients in the literature. As recurrence of MAC is not predictable, exision surgery with clear margins and minimum pathologic atypia can aid to decrease the rate of recurrence (2).
The most common utilized treatment modalities for MAC include wide local excisional surgery (WLE), Mohs micrographic surgery (MMS) and radiotherapy. Recurrence has been reported in using every type of treatment modalities above, even in patients with clear tumor margins (3,8, 15,26).
Regardless of the method chosen, complete removal of the tumor on its first occurrence is ideal as recurrent lesions are much more difficult to manage.
MMS offers the highest probability of clear surgical margins as it can detect subclinical extension while providing maximum tissue sparing (2,27).
Determining true margin status in the subset of MAC patients with perineural invasion (PNI) treated with surgical techniques can be problematic. Cutaneous carcinoma with PNI manifestation, behaves aggressively and increased rate of recurrence with wide extension have been observed. It has been reported in 17.5–59% of MAC patients (27).
WLE is another alternative, in which margin detection depends mainly on the histologic technique hired by the pathologist.
It is strongly recommended to perform complete excisional surgery with clear margins with long-term follow-up, because of high rate of recurrences; as it can recur even several years after the surgery (2,28). Also we should take surgical margins wider than clinical margins due to the infiltrative growth pattern of the tumor. Recurrence rate of WLE is about 17% to 60%, as reported in studies (2,8,29,30).
It is still challenging to define the role for definitive or adjunctive radiotherapy in, because of the rarity of disease and the uncommon use of radiotherapy for managing the disease. The majority of studies reported unclear details about hired techniques of radiotherapy for MAC lesions. Differences in radiotherapy techniques and sequencing also make it difficult to draw conclusions. There is evidence that radiotherapy can transform the MAC lesion into a new highly aggressive form, according to its clinical and histological features (31,32).
MAC has also been reported as a radiogenic secondary malignancy (33). 16 of 84 published MAC cases in the literature, have declared a history of prior exposure to radiations, with 19.05% incidence (8,17,19,28,31,34-44).
As the rate of MAC recurrence after monotherapy with radiotherapy is high (1,8,45), it is not commonly suggested to use radiotherapy as definitive monotherapy for patients with MAC. But as adjuvant therapy, it may be useful in subset of patients who have undergone WLE or MMS without achieving a tumor free margin and are at high risk of recurrence. Also it can be considered as treatment in patients who avoid to perform WLE or MMS, because of the disfiguring facial defects of surgery. Elderly patients may also be a good candidate for radiotherapy, particularly in those whose comorbidities make them poor surgical candidates.
The knowledge about hair transplantation is growing every day. In 1959, Dr. Orentreich developed it for the first time. He applied it as a therapeutic procedure on a patient suffering from androgenic alopecia (46).
Hair transplantation is used for covering the features of hair loss and it has become one of the main popular procedures in cosmetic field (particularly scars) now with satisfactory results (47).
Follicular unit transplantation (FUT) and follicular unit extraction (FUE) are common techniques hired for hair transplantation. In FUT technique, a band-shaped tissue of occipital region is used as donor, which results a linear scar. To avoid its complications, including scarring, FUE technique was introduced, in which, small units of hair follicles are harvested (47).
Osman et al. performed hair transplantation on the cleft lip area scar. They hired fat grafting procedure on twenty patients suffering from scar and alopecia. Then hair transplantation was performed three months after fat injection. After a one-year period of follow-up, patients declared noticable high level of satisfaction (48).
Also Soyeon et al. evaluated the results of hair transplantation for scar management in 25 cases (of 23 patients), in which burns, operation, and trauma resulted scar with hair loss on the scalp and the face (eyebrow, lip, and eyelid). After a 6 months period of follow-up, satisfactory report from hair follicle transplantation procedure was as excellent (44.4%), good (38.9%), fair (11.1%), and poor (5.6%) (49).
Transplanting the hair follicles on a tissue with scar is so difficult, due to the poor blood supplement and tenacity of the scar tissue. Also, a higher rate of success and favorable results is seen in patients with burned scar rather than incision scars, due to the deeper depth of incision scars (49).
So, we should always warn the patients that choosing hair follicle transplantation procedure for scar management, can be accompanied by secondary (or more) operations, for better cosmetic result.