Dermatofibrosarcoma protuberans (DFSP)[2] is a rare locally aggressive malignant cutaneous soft-tissue sarcoma. DFSP develops in the connective tissue cells in the middle layer of the skin (dermis).[3] Estimates of the overall occurrence of DFSP in the United States are 0.8 to 4.5 cases per million persons per year.[4][5] In the United States, DFSP accounts for between 1 and 6 percent of all soft-tissue sarcomas[6] and 18 percent of all cutaneous soft-tissue sarcomas. In the Surveillance, Epidemiology and End Results (SEER) tumor registry from 1992 through 2004, DFSP was second only to Kaposi sarcoma.
Dermatofibrosarcoma protuberans begins as a minor firm area of skin most commonly about to 1 to 5 cm in diameter. It can resemble a bruise, birthmark, or pimple. It is a slow-growing tumor and is usually found on the torso but can occur anywhere on the body.[7] About 90% of DFSPs are low-grade sarcomas. About 10% are mixed, containing a high-grade sarcomatous component (DFSP-FS); therefore, they are considered to be intermediate-grade sarcomas. DFSPs rarely lead to a metastasis (fewer than 5% metastasize), but DFSPs can recur locally. DFSPs most often arise in patients who are in their thirties but this may be due to diagnostic delay.
Commonly located on the chest and shoulders, the following is the site distribution of DFPS as was observed in Surveillance, Epidemiology, and End Results (SEER) database between 2000 and 2010.[5][8]
Bednar, or pigmented DFSP, is distinguished by the dispersal of melanin-rich dendritic cells of the skin. It represents 1–5 percent[10] of all DFSP occurring in people rich in melanin pigments. Bednar is characterized by a dermal spindle cell proliferation like DFSP but distinguished by the additional presence of melanocytic dendritic cells. It occurs at the same rate as DFSP on fairer skin and should be considered to have the same chances of metastasis.[11]
Giant cell fibroblastoma[2] contains giant cells, and is also known as juvenile DFSP.[14] Giant cell fibroblastomas are skin and soft-tissue tumors that usually arise in childhood. They are sometimes seen in association with dermatofibrosarcoma protuberans (DFSP, hybrid lesions) or may transform or recur as DFSP.[15][13]
Atrophic DFSP resemble other benign lesions such as morphea, idiopathic atrophoderma, atrophic scar, anetoderma or lipoatrophy. It behaves like classic DFSP. It commonly favours young to middle-aged adults. It has a slow infiltrative growth and a high rate of local recurrence if not completely excised.[13][16]
Sclerosing DFSP is a variant in which the cellularity is low, and the tumor consists of uniform bundles of collagen interspersed with more typical DFSP cells.[13]
Granular cell variant is a rare type in which spindle cells are mingled with richly granular cells, the granules being lysosomal, with prominent nucleoli.[13]
Fibrosarcomatous DFSP is a rare variant of DFSP involving greater aggression, high rates of local occurrences, and higher metastatic potential.[17] DFSP-FS are considered to be intermediate-grade sarcomas,[18] although they rarely metastasize (fewer than 5 percent of cases).
DFSP is a malignant tumor diagnosed with a biopsy, when a portion of the tumor is removed for examination. In order to ensure that enough tissue is removed to make an accurate diagnosis, the initial biopsy of a suspected DFSP is usually done with a core needle or a surgical incision.[21]
Clinical palpation is not entirely reliable for ascertaining the depth of a DFSP infiltration. Magnetic resonance imaging (MRI) is more sensitive addressing the depth of the invasion on some types of DFSP, particularly large or recurring tumors,[22][23] though MRI is less accurate for identifying infiltration to head and neck tumors.
Due to the rarity, initial presentation of flat plaque (skin hardening) and the slow-growing nature of DFSP, it may be months to years without a protuberance (bump). The dissonance between the name of the neoplasm and its clinical presentations may cause a majority of patients to experience a diagnostic delay. A 2019 research study found out of 214 patients a range between less than a year to 42 years before diagnosis (median, four years) from patients noticing a symptom to diagnosis.[24]
Currently, a majority of patients (53%) receive a misdiagnosis by health care providers. The most frequent prebiopsy clinical suspicion included cyst (101 [47.2%]), lipoma (30 [14.0%]), and scar (17 [7.9%]).[24]
It has been suggested an alternative term for DFSP should be dermatofibrosarcoma, often protuberant.[24]
It is suggested that DFSPs may enlarge more rapidly during pregnancy. Immunohistochemical stains for CD34, S-100 protein, factor XIIIa, and estrogen and progesterone receptors were performed on biopsy specimens. The tumors showed the expression of the progesterone receptor. As with many other stromal neoplasms, DFSPs appear to express low levels of hormone receptors, which may be one factor that accounts for their accelerated growth during pregnancy.[25]
Wide local excision (WLE) was the gold standard for treating DFSP but is currently under reevaluation. Presently in the United States, WLE may be suggested after the recurrence of MMS. Larger resection margins are suggested for WLE than MMS. Recurrence rate with WLE is about 8.5% with a lower recurrence rate related to wider excision.[28]
DFSP characteristic features are its capacity to invade surrounding tissues, to a considerable distance from the central focus of the tumor in a "tentacle-like" fashion. This fact, coupled with diagnostic delay, may lead to inadequate initial resection. Inadequate initial treatment results in larger, deeper recurrent lesions, but these can be managed by appropriate wide excision.[29]
DFSP is a radioresponsive tumor; radiation therapy (RT) is not used as the first choice for treatment. Conservative resection through MMS or WLE is attempted first. If clear margins are not achieved RT, or chemotherapy is recommended.[30]
DFSP was previously regarded and nonresponsive to standard chemotherapy.[31] In 2006 the US FDA approved (imatinib mesylate) for the treatment of DFSP.[32] As is true for all medicinal drugs with name ending in "ib," imatinib is a small molecular pathway inhibitor; imatinib inhibits tyrosine kinase. It may be able to induce tumor regression in patients with recurrent DFSP, unresectable DFSP, or metastatic DFSP.[33] There is clinical evidence that imatinib, which inhibits PDGF-receptors, may be effective for tumors positive for the t(17;22) translocation. It is suggested that imatinib may be a treatment for challenging, locally advanced disease and in the rare metastatic cases. It was approved for use by adult patients with unresectable, recurrent and/or metastatic dermatofibrosarcoma protuberans (DFSP).[34]
Distant hematogenous metastases are extremely rare.[35]Metastases to regional lymph nodes are rarer and are most likely in patients who have had multiple local recurrences after inadequate surgical resection.[36] Repeatedly recurring tumors have an increased risk for transformation into a more malignant form (DFSP-FS). The lungs are most frequently affected, but metastases to the brain,[37] bone,[38] and other soft tissues are reported.
DFSP is not extensively studied due to its rarity and low mortality. The majority of studies are small size case studies or meta-analysis.
The most extensive research study to date was Perspectives of Patients With Dermatofibrosarcoma Protuberans on Diagnostic Delays, Surgical Outcomes, and Nonprotuberance.[24] The lead researcher, Jerad Gardner, spoke at a TED Talk in February 2020 on the topic.[39]
R. W. Taylor, in 1890,[40] first identified DFSP as a keloid sarcoma. Later in 1924, Ferdinand-Jean Darier and Ferrand identified it as a progressive recurrent dermatofibroma. In 1925, E. Hoffmann[41] coined the term dermatofibrosarcoma protuberans. Bednar tumor was first described by Bednar in 1957.[42][43]
^ abKreicher, Kathryn L.; Kurlander, David E.; Gittleman, Haley R.; Barnholtz-Sloan, Jill S.; Bordeaux, Jeremy S. (January 2016). "Incidence and Survival of Primary Dermatofibrosarcoma Protuberans in the United States". Dermatologic Surgery. 42 (Suppl 1): S24–31. doi:10.1097/DSS.0000000000000300. ISSN1524-4725. PMID26730971. S2CID12966671.
^Kransdorf, M. J. (January 1995). "Malignant soft-tissue tumors in a large referral population: distribution of diagnoses by age, sex, and location". American Journal of Roentgenology. 164 (1): 129–134. doi:10.2214/ajr.164.1.7998525. ISSN0361-803X. PMID7998525.
^Reimann, Julie D. R.; Fletcher, Christopher D. M. (September 2007). "Myxoid dermatofibrosarcoma protuberans: a rare variant analyzed in a series of 23 cases". The American Journal of Surgical Pathology. 31 (9): 1371–1377. doi:10.1097/PAS.0b013e31802ff7e7. ISSN0147-5185. PMID17721193. S2CID1268848.
^Abbott, Jared J.; Oliveira, Andre M.; Nascimento, Antonio G. (April 2006). "The prognostic significance of fibrosarcomatous transformation in dermatofibrosarcoma protuberans". The American Journal of Surgical Pathology. 30 (4): 436–443. doi:10.1097/00000478-200604000-00002. ISSN0147-5185. PMID16625088. S2CID23911032.
^Sirvent N, Maire G, Pedeutour F (May 2003). "Genetics of dermatofibrosarcoma protuberans family of tumors: from ring chromosomes to tyrosine kinase inhibitor treatment". Genes Chromosomes Cancer. 37 (1): 1–19. doi:10.1002/gcc.10202. PMID12661001. S2CID36985697.
^Patel KU, Szabo SS, Hernandez VS, et al. (February 2008). "Dermatofibrosarcoma protuberans COL1A1-PDGFB fusion is identified in virtually all dermatofibrosarcoma protuberans cases when investigated by newly developed multiplex reverse transcription polymerase chain reaction and fluorescence in situ hybridization assays". Hum. Pathol. 39 (2): 184–93. doi:10.1016/j.humpath.2007.06.009. PMID17950782.
^Serra-Guillén, Carlos; Sanmartín, Onofre; Llombart, Beatriz; Nagore, Eduardo; Deltoro, Carlos; Martín, Isabel; Borella-Estrada, Rafael; Requena, Celia; Martorell-Calatayud, Antonio; Cervera, Jose; Guillén, Carlos (November 2011). "Correlation between preoperative magnetic resonance imaging and surgical margins with modified Mohs for dermatofibrosarcoma protuberans". Dermatologic Surgery. 37 (11): 1638–1645. doi:10.1111/j.1524-4725.2011.02077.x. ISSN1524-4725. PMID21679274. S2CID23878054.
^Kransdorf, M. J.; Meis-Kindblom, J. M. (August 1994). "Dermatofibrosarcoma protuberans: radiologic appearance". American Journal of Roentgenology. 163 (2): 391–394. doi:10.2214/ajr.163.2.8037038. ISSN0361-803X. PMID8037038.
^Parlette, L. E.; Smith, C. K.; Germain, L. M.; Rolfe, C. A.; Skelton, H. (November 1999). "Accelerated growth of dermatofibrosarcoma protuberans during pregnancy". Journal of the American Academy of Dermatology. 41 (5 Pt 1): 778–783. doi:10.1016/s0190-9622(99)70023-x. ISSN0190-9622. PMID10534646.
^Khatri, Vijay P.; Galante, Joseph M.; Bold, Richard J.; Schneider, Philip D.; Ramsamooj, Rajendra; Goodnight, James E. (November 2003). "Dermatofibrosarcoma protuberans: reappraisal of wide local excision and impact of inadequate initial treatment". Annals of Surgical Oncology. 10 (9): 1118–1122. doi:10.1245/aso.2003.03.581. ISSN1068-9265. PMID14597453. S2CID41310745.
^Suit, H.; Spiro, I.; Mankin, H. J.; Efird, J.; Rosenberg, A. E. (August 1996). "Radiation in management of patients with dermatofibrosarcoma protuberans". Journal of Clinical Oncology. 14 (8): 2365–2369. doi:10.1200/JCO.1996.14.8.2365. ISSN0732-183X. PMID8708729.
^Rutgers, E. J.; Kroon, B. B.; Albus-Lutter, C. E.; Gortzak, E. (June 1992). "Dermatofibrosarcoma protuberans: treatment and prognosis". European Journal of Surgical Oncology: The Journal of the European Society of Surgical Oncology and the British Association of Surgical Oncology. 18 (3): 241–248. ISSN0748-7983. PMID1607035.