Combined malignant melanoma and basal cell carcinoma tumor of the intermingled type

A Rare Case of a Basomelanocytic Tumor

ABSTRACT

Basal cell carcinomas and melanoma are common cutaneous malignancies. However, the development of a basomelanocytic tumor that simultaneously includes elements of melanoma and basal cell carcinoma is extremely rare. We present the case of an 84-year-old man who presented with a nonpigmented, nonulcerated pink nodule of his left upper back and discuss the current management recommendations for basomelanocytic tumors.

Metastatic melanoma and rare melanoma variants: a review

The histopathological diagnosis of melanoma is fraught with potential pitfalls. In the setting of cutaneous metastatic melanoma, it is important to recognise the various histological patterns that can be encountered from the more common to the rare, including epidermotropic, folliculotropic, naevoid, and blue naevus-like. In addition, melanoma is notorious for phenotypic plasticity. Thus, there are many different subtypes and cytomorphological variations that can be difficult to recognise as melanoma, particularly in the recurrent or metastatic setting. Select melanoma variants including primary dermal, clear cell, plasmacytoid, signet ring cell, small cell, myxoid, rhabdoid, and dedifferentiated melanoma will be discussed, in addition to composite melanocytic neoplasms. This review is intended to remind the practitioner of key concepts of metastatic disease and select rare melanoma variants, while providing practical guidelines for accurate diagnosis.

Multiple Skin Neoplasms at One Site (MUSK IN A NEST): A Comprehensive Review of Basal Cell Carcinoma and Benign or Malignant "Collision" Tumors at the Same Cutaneous Location

Multiple skin neoplasms at one site (MUSK IN A NEST), initially referred to as a collision tumor, describes the occurrence of two or more benign or malignant neoplasms that are adjacent or intermingled at the same cutaneous site. A mononeoplastic cutaneous tumor refers to a single tumor at any cutaneous site. Two, three, four, five, and six tumors at the same site are described as dineoplastic, trineoplastic, tetraneoplastic, pentaneoplastic, and hexaneoplastic cutaneous tumors, respectively; the prefixes are based on the numerical multiplier used by the International Union of Pure and Applied Chemistry (IUPAC). MUSK IN A NEST can be classified based upon their mechanism of pathogenesis-either being composed of mixed clones of cells (clonalium, which has three subtypes: collision, colonization, and combination) or the same clone of cells that has undergone clonal evolution (clonalidem, which has one subtype: biphenotypic). Basal cell carcinoma (BCC)-associated MUSK IN A NEST can be observed with either benign tumors, malignant tumors, or both. Nevi and seborrheic keratoses are the most common benign tumors associated with BCC; melanoma in situ and invasive melanoma are the most commonly reported malignant tumors associated with BCC. The definitive etiology of BCC-associated MUSK IN A NEST remains to be established-whether the development of the BCC at that site occurs as a direct or indirect consequence of the coexisting neoplasm or whether the occurrence of the BCC and the other neoplasm is merely the result of a coincidental juxtaposition of the tumors.

Basosquamous carcinoma and melanoma collision tumor in a child with xeroderma pigmentosum

Xeroderma pigmentosum (XP) is a rare autosomal recessive genodermatosis associated with hypersensitivity to ultraviolet radiation (UVR), being due to defects involving the nucleotide excision repair pathway. Patients with XP are prone to develop multiple cutaneous neoplasms including non-melanoma skin cancers and melanoma. Collision tumors in patients with XP have been reported in the literature including the following lesions, actinic keratosis, basal cell carcinoma, squamous cell carcinoma, and in situ melanoma. Herein, we present a rare collision tumor composed of melanoma and basosquamous carcinoma in a 13-year-old XP patient and describe the dermoscopic features.

Cutaneous neoplasms composed of melanoma and carcinoma: A rare but important diagnostic pitfall and review of the literature

We report two cases of combined cutaneous tumors composed of melanoma and carcinoma. The first tumor presented as a 5-mm pink-blue macule over the right zygomatic arch in an 85-year-old man. Shave biopsy and immunohistochemical studies revealed that the tumor was composed of melanoma (highlighted by SOX10 and MART-1, with high Ki-67 proliferative index) intermixed with nodular basal cell carcinoma (highlighted by pan-cytokeratin and Ber-EP4). The neoplastic melanocytes were confined to the basal cell carcinoma nodules, and a diagnosis of combined melanoma in situ and basal cell carcinoma was rendered. After therapeutic excision, the patient was disease-free at 9 months after the initial diagnosis. The second tumor presented as a 6-mm pink-brown crusted papule on the right forehead in an 89-year-old man. Shave biopsy and immunohistochemical studies revealed that the tumor was composed of malignant melanoma (MM) (highlighted by S100 and MART-1) intermixed with squamous cell carcinoma (SCC) (highlighted by cytokeratin and p63), and a diagnosis of combined MM-SCC was rendered. These two cases highlight the importance of recognizing these rare types of melanocytic-epithelial cutaneous neoplasms to arrive at an accurate diagnosis that may inform appropriate disease stage and therapy.

Basomelanocytic Neoplasms: A Report of Two Similar Tumors With Divergent Treatments

Basomelanocytic neoplasms are tumors consisting of elements of both basal cell carcinoma and melanoma. These tumors are exceedingly rare and present a unique challenge as to how the melanoma component should be classified. Due to the paucity of cases, there are no clear-cut evidence-based guidelines as to how these tumors should be staged and which treatment options provide the optimal outcome. We present 2 separate patients with similar cases of colonizing basomelanocytic tumors that were treated in drastically different ways, highlighting the differing approaches to treatment. We discuss theses treatment modalities and the challenges inherent to diagnosing and treating basomelanocytic neoplasms.

High-Risk BCC Of the Lower Eyelid in Patient with Presternal Located Cutaneous Melanoma and BCC Of the Shoulder: Melolabial Advancement Flap Combined with Undermining Surgical Approach As Promising Complex One Step Treatment Option!

BACKGROUND:

It is assumed that the occurrence of keratinocyte and melanocytic tumours is multifactorial driven. Certain risk factors such as solar radiation, p53 protein and Melanocortin-1 receptor (MC1R) prove to be common to their development, which at the same time shows that their simultaneous manifestation in the same patients, for example, is quite possible. Such a manifestation could be observed as collision tumours within the same solitary lesion or as a simultaneous occurrence within two completely different lesions that are clearly distinguished from one another.

CASE REPORT:

An 85-year-old patient is presented with three primary cutaneous tumours located in region presternal, infraorbital sinistra and scapularis extra. The lesions were removed during a single surgical session. For the high-risk basal cell carcinoma (BCC) in the lower eyelid, the so-called melolabial advancement flap was applied, and for the tumours located in the other two areas, the undermining surgical approach was applied. The subsequent histological analysis found that the case referred to two keratinocyte tumours (BCC) and one melanocyte tumour (cutaneous melanoma).

CONCLUSIONS:

The patient presented is interesting with regard to 1) the simultaneous presentation of three primaries with different localization (so far not described in the world literature, namely 2 basal cell carcinomas and one melanoma in the same patient concurrently), 2) one of the basal cell tumours belongs to the group of high-risk (according to the localization) and meanwhile advanced BCC (according to the infiltration degree of the underlying tissue-infiltration of the musculature) and 3) their simultaneous successful surgical treatment in a single surgical session under local anaesthesia.

Colliding, colonizing or combining? Four cases illustrating the unique challenges presented by melanoma arising in conjunction with basal cell carcinoma

Biphasic lesions comprised of melanocytic and epithelial components are rare entities believed to arise either as a collision of 2 histologically distinct lesions in the same anatomic location or as a singular progenitor tumor differentiating along 2 differing lineages. Regardless of mechanism of origin, these tumors present unique challenges in pathologic interpretation and in determining appropriate measurements, which assigns subsequent prognosis to the patient. We present 4 tumors of melanoma co-existing with basal cell carcinoma (BCC) and discuss relevant literature regarding these biphasic entities. Patients consisted of 3 males and 1 female, ranging in age from 62 to 93, with lesions located on the shoulder, frontal scalp, forearm and nose. Three of 4 lesions showed melanoma cells limited to BCC tumor lobules, without evidence of direct dermal invasion by melanoma cells, raising the question of whether or not these tumors should be classified as in situ or invasive melanoma. These cases highlight the complexity that such lesions pose to dermatopathologists, in terms of their uncertain origin and variable microscopic appearance. In the absence of data regarding outcomes for these tumors (given their rarity), it is important to utilize a case-by-case approach, with careful clinical correlation and appropriate use of ancillary techniques.

Pigmented squamous cell carcinoma: case report and importance of differential diagnosis

A few cases of pigmented squamous cell carcinoma affecting the skin and the ocular and oral mucosa of the elderly have been described in the literature. The disease manifests itself as papular and nodular erythematous or pigmented lesions. The main clinical differential diagnoses are pigmented basal cell carcinoma and melanoma. Histopathological examination is characterized by proliferation of atypical squamous cells with formation of horn pearls permeated by dendritic melanocytes. For this reason, a careful diagnosis is necessary to rule out other tumors that show melanin pigment. Surgical removal is the indicated treatment and the prognosis is similar to the classical squamous cell carcinoma. We report a case of pigmented squamous cell carcinoma with diagnosis confirmed by histological and immunohistochemical examinations.

Melanoma in situ colonizing basal cell carcinoma: a case report and review of the literature

Colonization of basal cell carcinoma (BCC) by melanoma cells is a unique and uncommonly reported cutaneous entity. We describe a bluish nodule on the left forearm found during routine skin cancer surveillance examination with suspicious dermatoscopic findings including central-blue-white veil, sparse atypical dots, and a surrounding pink vascular blush with focal irregular tan-brown pigmentation at the periphery. Histopathology demonstrated a pigmented BCC with an overlying and adjacent melanoma in situ (MIS), as well as colonization of the BCC nodule by melanoma cells. We performed a review of the literature on the topic and discuss other presentations of cutaneous neoplasms composed of both BCC and melanoma, including collision, combined, and biphenotypic tumors. The prognostic and management challenges inherent to this distinctive neoplasm are summarized.

A colonization of basal cell carcinoma by malignant melanoma in situ resembling a malignant basomelanocytic tumor

We report a case of colonization of basal cell carcinoma (BCC) by malignant melanoma in situ (MIS) simulating a malignant basomelanocytic tumor. A biopsy of a pigmented lesion present on an 83-year-old man's scalp displayed intimate admixing of basaloid and melanocytic cells. This seemingly inseparable combination of BCC and neoplastic melanocytes has been referred to as a malignant basomelanocytic tumor. However, our case also displays an adjacent component of MIS, thus favoring colonization of BCC by MIS as the etiology. To our knowledge, this is the third case report of colonization of BCC by MIS resembling a malignant basomelanocytic tumor.

Malignant melanoma within squamous cell carcinoma and basal cell carcinoma: is it a combined or collision tumor?--a case report and review of the literature

We report a case of a very unusual combined and collision basosquamous melanocytic malignant tumor on the chest of an 84-year-old man. To our knowledge, this is the first case report describing this entity. We attempt to address the diagnostic challenge and the clinical and histological characteristics of these rare neoplasms with a review of the English literature to further categorize and summarize what has been previously reported about these extraordinary tumors.

Colonisation of basal cell carcinoma and actinic keratosis by malignant melanoma in situ in a patient with xeroderma pigmentosum variant

Although malignant melanoma (MM) and both basal cell carcinoma (BCC) and actinic keratosis (AK) are sun-induced lesions, the coexistence of these entities at the same anatomical site (collision tumour) is exceedingly rare. We report the case of a 54-year-old woman with a known history of xeroderma pigmentosum variant (XPV) who presented with 2 separate skin lesions over the middle and upper right forearm, respectively. The clinical impression was that of BCCs or squamous cell lesions. On histological examination, both specimens showed features of melanoma in situ (MIS). In the first lesion, MIS merged with and colonised a superficial and focally invasive BCC. In the second lesion, MIS merged with an AK. No separate invasive nests of malignant melanoma were seen in either specimen. The atypical melanocytes were highlighted by Melan-A and HMB-45 immunostaining, whereas the epithelial cells in both the BCC and AK stained with the pancytokeratin MNF-116. The patient had a previous history of multiple MMs and non-melanomatous skin cancers and finally developed widespread metastatic malignant melanoma, which proved fatal. The rare and interesting phenomenon of collision tumours may pose diagnostic difficulties. To our knowledge, this is the first reported simultaneous presentation of cytologically malignant collision tumours in a patient with XPV.

A rare case of a cutaneous squamomelanocytic tumor: revisiting the histogenesis of combined neoplasms

We describe what we believe to be the seventh report of a combined tumor with histologic features of both malignant melanoma and a squamous cell carcinoma, a squamomelanocytic tumor. An 82-year-old woman presented with a nondescript, skin-colored, firm papule on her nose. Histology showed 2 different neoplastic cell proliferations: atypical squamoid cells and irregularly shaped nests of atypical pigmented epithelioid cells (melanocytes) arranged in small to large nests at the dermal-epidermal junction and within the epidermis. Both components were closely admixed and restricted to the epidermis. Immunohistochemistry showed diffuse cytoplasmic reactivity for pancytokeratin in all areas supporting the histopathologic features of a squamous cell carcinoma. S-100 and melanoma antigen recognized by T cells 1 did not stain these areas and showed strong selective positivity for the atypical melanocytic component. A true malignant proliferation of 2 distinct cell phenotypes due to close paracrine interactions is our favored interpretation because of the intimate admixture, distinct immunohistochemical pattern, and unique histologic features. Perhaps, chronic sun damage (facial location and advanced age) and reduced immunity (history of other malignancies, particularly recent history of a basal cell carcinoma) played a complementary role for the development of the squamomelanocytic tumor.