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Polymorphous low grade adenocarcinomas (PLGA) are minor salivary gland neoplasms with a predilection for intraoral sites. Extraoral location of the tumor is rare and the nasal tumors are less than 1%.[1] It generally involves the palate, but it has also been reported in the base of the tongue, upper lip, buccal mucosa, tonsil, and retromolar pad.[2] So far, only 3 cases have been reported, where PLGA presented as a sinonasal mass.[3,4] Histologically, PLGA resembles pleomorphic adenoma , benign mixed tumor and to an extent, to adenoid cystic carcinoma.We present a case of PLGA, which presented as a nasal polyp.
A male patient presented to the Dept. of ENT with a history of nasal obstruction and a single episode of epistaxis. There was no history of an upper respiratory tract infection or trauma. Nasopharyngoscopic examination revealed a polypoidal structure in left nasopharynx. No cervical lymph node enlargement was found. The FNAC of the polypoidal structure showed cellular smears. The cells had high N/C ratio, scanty cytoplasm, nuclei of variable chromatin density and inconspicuous to conspicuous nucleoli. Beaded fragments of hyaline stroma were present between cell clusters.[Fig. 1] A diagnosis of adenoidcystic carcinoma was made. Polypectomy was done and sent for histopathological examination. HPE revealed mildly pleomorphic plump columnar cells arranged in tubular, cribriform, solid and fasicular patterns. No area revealed papillary configuration. Mitotic activity was low. Basement membrane material was found associated with the tumor cells. Peripherally the tumor cells revealed infiltrative pattern with foci of neurotropism[Fig 2], suggesting a diaganosis of Polymorphous low grade adenocarcinoma.
Since the
original
description of these tumors, PLGA has been recognized as a distinct
salivary gland tumor that has a predilection to occur in the minor
salivary
glands and is associated with slow growth and indolent biology. PLGA
occurs over a wide age range but does not seem to occur in the first
or second decades of life. There is a nearly 2:1 female to male ratio
for the patients. Clinically,wide age range has been described(23 to
94 years). PLGA in women tends to occur at a slightly younger age (56.6
years) compared with male patients (59.7 years), but there is no
statistically
significant difference. The typical clinical presentation of PLGA is
that of an asymptomatic mass located within the oral cavity. Rare
intraosseous
cases have been described. Nasal cavity and nasopharyngeal involvement
in PLGA is rare(1% and 0.5%). To date only few cases have
been reported in nasal cavity. Clinical symptomatology ranges in
duration
from a few days to 40 years, with an average length of symptoms of 27
months. Patients who present with pain, bleeding, or ulceration do not
have more aggressive disease nor are they more prone to develop
recurrences. Grossly, the tumor is usually unencapsulated, The differential diagnoses of PLGA are adenoid cystic carcinoma and pleomorphic adenoma. Both adenoid cystic carcinoma and pleomorphic adenoma can have similar architectural patterns; however, the cells in ACC tend to be smaller with hyperchromatic nuclei and coarser chromatin. Mitoses are numerous. The infiltrative growth pattern and neurotropism are an important diagnostic clue favouring PLGA, when the differential includes pleomorphic adenoma. Although, the tumor has variable architectural patterns, the cells have minimal cellular pleomorphism. Local recurrences can occur. Rarely regional lymph node metastasis and distant (lung) metastasis have been documented. PLGAs chiefly involve the minor salivary glands. Only few cases involving the major salivary glands have been reported so far. A definitive diagnosis of PLGA is established by detecting this
characteristic
histological feature of the resected tumor. The patient has been
followed-up
without evidence of recurrence and did not undergo radiation therapy.
We suggest that radiation therapy may be reserved for patients with
recurrence and regional metastasis. Charous DD, Cunnane MF, Rosen MR,Keane WK. Recurrent polymorphous low-grade adenocarcinoma manifesting as a sinonasal mass: a case report. Ear Nose and Throat Journal. June 2005. Wenig BM, Harpaz N, DelBridge C. Polymorphous low-grade adenocarcinoma of seromucous glands of the nasopharynx. A report of a case and a discussion of the morphologic and immunohistochemical features. Am J Clin Pathol 1989;92:104–9. Lengyel E, Somogyi A, Godeny M, et al.. Polymorphous low-grade adenocarcinoma of the nasopharynx. Case report and review of the literature. Strahlenther Onkol 2000;176:40–2. Castle JT, Thompson LDR, Frommelt RA, Wenig BM, Kessler HP. Polymorphous Low Grade Adenocarcinoma-A Clinicopathologic Study of 164 Cases. Cancer 1999;86:207–19. |
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